Pippin areas of research:

Making this clear from the off, this isn't an out and out list of things Pippin has planned, its things Azhrit could find out about, Pippin does have ways and means of keeping some things to himself (Least of which is hiding them beyond the huge ass vault door that leads into the catacombs and that you need a fair few people to open, if you want to send Gnawtooth in to find shit out, sure, go nuts but if he dies it ain't on my head.)
But, most of his notes are kept in either of his moderately accessible offices it seems (Moderately accessible if you're Gnawtooth-Azhrit that is, heavy arcane locks, traps, undead tigers that hang about the place, ect), as well as in the books he donates to the Caster tower library once he's done with them.
As for the notes you can find, they're usually fairly well hidden and these are the highlights, notes of interest, for every topic here there's half a dozen notes on elvish wine, Necromantic anatomy, ancient history, opera, law writing, politics and the mating habits of the Sphinx, they're often mixed in together and these notes are sometimes in code inside the other notes. But Azhrit has a hell of a lot of time; So, areas he's taken interest in/notes you can find, anything indented is stuff you've found he's been looking into while showing interest in that particular project.

>Full research notes on the Prince in Chains, history, nature, religious notes and biographies from Kuthonites and others that have encountered him, usually mixed in with information on his relationship with Shelyn when he was still sane.
	>Loose Leaf notes on the nature of self sacrifice and its power, taken from a group of cultists of that crazy no eye empyreal lady, including contact details for the cult. Several letters back and forth ending with an agreement to do a service for notes on their empyreal rituals, mentions of the Taker of Eyes
	>Geographic maps of several possible gateways to other planes, mostly in shadow-plane heavy areas, focusing in on one particular area in the forests of Brevoy that's detailed as a thin area between the shadow plane and the material plane, heavy research into the history of the place, didn't turn much up.
	>A bound and trapped leather book of designs for torture devices, some very creative ones from as far as Nidal, each worse than the last, eventually leading into his own designs, seems to be leading towards a specific design, focusing down on skin-flensing, seems he moved out of the book when he reached the last pages and there are probably further notes in existence but they can't be found.
	>Various details on calling up Shelyn, times it has happened in the past, ect and the dynamic between her and Zon-Kuthon, particularly how her priesthood are protected from his tastes and followers.
	>Several sets of heavy chains that appear to have been part of a relic at some point, possibly from the Prince himself.

>Detailed notes on Geb, history, Geography, sociology, its leaders, Geb himself, Azlani, the blood lords (Full histories of all, or at least those he can find histories on)
	>Huge chunks of detail on Azlani, very much focused on the bloodstones, their possible locations and how they would in theory interact with her, listings of ways to increase willpower and the like.
		>A very, very detailed contract detailing out the calling up of an unknown outsider to try and find the location of at least one of the Bloodstones.
		>Details reports on the life and unlives of her entire harem, with a numerical order by their names, Seldeg Bheldis appears to be first on the list.
	>Letters to Lastwall, all in code, negotiating for blueprints of Gebbian border forts.
	>History of that one noble family with that ghost that Pippin and Azhrit encountered, along with past accounts of how the Gebbian government acts upon traitors, several pounds of potential blackmail material on the household in careful filing, as well as a family tree measured out to 3 generations from the direct bloodline, highlights on women (Bar undead), potential innocent parties and children
	>Psychological reports on Geb himself
		>Details on a magic item called the 'Eternal Egg', created by a Nexian Arclord to try and attract the attention of Nex.
		>Large amount of information on the Petrified Maiden
	>Khmet Khanrah and his Cohorts, a rather detailed report on a group of fairly powerful ghosts that appear to have serious beef with Geb

>Brazen Clutch, casual report on sending a group of merchants to go raid a Katapesh Aspis Consortium safe house for a group of Brass dragon wyrmlings.

>Plans to reanimate the Bones of the Challenger (Noted in margin: Req acs to PoG. Bring Gigante, he'll enjoy the holiday')

>Designs for a blood draining device on an industrial scale, capable of producing enough blood to feed dozens of vampires each day.

>Several filing cabinets of wage packets and taxes for various ventures in the Stagfell, holy shit does Pippin own a lot of property, most of it by proxy and deeds, rather than directly declared; only thing of note is a recent wage packet that appears to have been signed by a Grig for 'Services rendered unto boring people'

>Black Blood of Orv, some information, not much, blue prints for a possible tunnel leading down to the land itself from the surface.
	>Black Desert and information on The Bloodsoaked Bones of Urgathoa, possibly planning to hijack them?

>Geographic designs for dropping the Capital of the Holds of Belkzen onto the Drow Capital, plan seems to have been abandoned for moral reasons (Feel free to use Azhrit, you got less moral computations than Pippin, go nuts)

>Sarkosis and the World Wound, hidden in a secret area on the underside of his desk.
	>Several Segments on a place known as Ice Rift Castle, appears to have been a Mendev crusader installation during the 1st crusade, no present day information can be found on it.
	>Information on the Wardstones and their creator, the Phoenix now known as Rain-of-Embers, several hypothetical air engagements and strategies for killing her.
	>Storasta and its huge amount of Restless spirits, as well as information on the guardian at its core, Carrock the Treant.
		>Straight up map plans for transversing the Undying Herds of Storasta across the continent as a possible source of one of cavalry undead.
	>Plans to contact some sort of druidic order deep in the world wound and gain their alliance, various spells researching into purifying damned souls and using natural sources to do so.
	>Information on the interactions between the undead and the world wound, turns out the dead are fairly immune to insanity and abyssian influences, what with being dead. Battle plans for an attack on Storasta, requires at least 20 Wyrmsbreath Fire cannons, minimum.
	>Tower of Yath, a full account of its destruction and people who have been near it since, mentions of Isilda, its one time owner as possibly being still alive.
	>Dozens of Reports on an area known as the Mammoth Graveyard, recently corrupted by the World Wound.
	>A single ragged map of a place called the Blackearth Cairn, carved into what is most likely cured human skin, Pippin has marked a crown at the center of it, rolled in the scroll are papers from pre-worldwound Sarkosia, detailing their royal crown, an item known as the Crown of Feasting Raven.
	>Raliscrad, full details of its history and a contracted agreement with a lesser psychopomp agreeing a half dozen undead (Not created by Pippin) laid to rest in return for information on Atzemsira, who appears to be leader of some sort of resistance in that city.
	>A half dozen obviously corrupted feathers and a copy of a letter to Eliandra, of Pulura's Fall offering assistance to come some time in the next 18 months.

>Research into Naderi, Goddess of romantic death and suicide, her past with Shelyn, her fall, her current leanings towards Urgathoa, several possible locations of where she might be hiding.
	>Books on the Plane of Positive Energy and an obscure and heretical text by a Jyoti exile, describing a place at the core of the plane where the flowers of the gods themselves grow free and wild.
		>Several variant copies of a poem/song describing the deaths of two lovers, reaching back through history as far as the Age of Torment, includes several very detailed maps of Avistian through history with possible locations that match the details given in the song.

>Plans to visit the City of Brass and trade

>Plans to visit the Fey Market and leave Hanley there.

>Possibly Hijacking the Skyborne Keep, notes that only Gigante would be able to command it.

>Galtish history, culture and possible methods for bringing an end to the Final Blades.
	>Details on the Derro-Dungeon of Dread alliance taken from galtish secret files, several possible locations for the area, several dates for fly overs and finally a date for the raid, occurred several months ago.
	>A sample of glowing white blood, possibly Aasimar or Celestial, labelled as 'Fm Pznr, Cr Glt Mdns? Sch ftr'
	>Several possible routes for shipments into/out of Galt, bypassing the River Kingdoms or passing through less observant River Kingdoms. A few blueprints of major Galtish cities, those with Final Blades in them mostly, alongside witness statements of the early days of the Gray Gardeners.

>Ustalav, a huge repository of information kept under heavy locks in the basement of the Caster tower.
	>Ground of Tears, turns out his Grandfather was involved in that situation but its all kept very carefully coded and details are vague at best, Pippin appears to be planning to make pilgrimage there at some point.
		>Details of an upcoming trip to this are with Gabriel, underlined note in margin reads 'Visit Opera house for Opera plans, Do NOT visit Marian Leigh'
	>Castle Konquist and its master, totes-not-Vlad, a semi-area of interest
	>Gravecharge, listed as a 'possible source of an army in situations dire.
	>Kalexcourt, large chunk of info on this place, research into the Witch-King at its core, lots of info on the Kellid in Ustalav in general really.

>Mordant Spire, surprising amount of interest in this, all the notes are kept in a lunar cipher making them a ball ache to decode.
	>Several Historic documents on the elven goddess of the moon.
	>Documents on the ruins of Azlant and how those dick elves are keeping them to themselves.

>Kyonin, lotta notes on Kyonin, spread out amongst the others mostly and linked to other aspects
	>Endless Masoleum, calculations on how many corpses might be inside, answer tots up in the 10,000s
	>Treerazer, there's a lot of information on Treerazer, down to the finest details, he could write books with the number of books, scrolls, animal skins, carved goat bones and bark burnings he has on Treerazer, there's also a fair number of divinations on the subject of the big green dinosaur himself. Designs of a number of siege engines, fairly evident that Pippin is planning to toe-to-toe the Barney Wannabe at some point, big and carefully written list of possible effects on the area, turns out that removing Clerical powers from an entire chunk of cultists gives mad help to people fighting them.
		>Heibarr is often mentioned leafed in among Treerazer information, there's cross references into an index of some kind
		>Historical accounts of the high temple of Calistria and its location, deep in the Tanglebriar.

>Brevoy, the upcoming war mostly, sheaf's of notes on the Valley of Fire, possible players in the war, he's found the identity of the Spymaster of Brevoy somehow and is planning to 'borrow an eye' from him whatever that means.
	>A huge number of notes carefully coded and double binded notes on a ritual to stop the war, obviously keeping exact details hidden somewhere else on what it would do or how, but the notes also contain a list of historical massacre sites, including Galt, the Ground of Tears and the Furrows in Ustalav

>History of the Lorics Fells, partial maps of the swampy area, strategic maps of monsterous encampments and areas that are more habitable, troop movement maps and possible locations for the lost dwarven quarry-stronghold at the heart of it.
	>Information on the Sea-brack town of Inner-Sea, particularly their non-evil Hag population, ways he could gain their alliance and assistance, areas in the Lorics fells with heavier salt concentrations, so on.
	>Economic listings for the prices of the Marble sold to Galt before the revolution (Also found in the Galt files)

>Whispering Tyrant, oddly sparse these notes, probably keeping the full details and any used up research books somewhere else under lock and key. Those he has shared mostly seem to detail about the city of Golden Death and calculations on how much gold it might contain (The answer is: Jesus Fuck, rolling in the money yo)
	>Messages in Dark Folk and an agreement with an unknown Dark Stalker to 'open the silent places' in return for 'Leading my men to the Well', seems to be an ongoing negotiation, possibly involving Pippin gaining a crew of Dark Folk to call his own
	>Horns of Naraga legend and a map of the Isle of Terror
		>A fair amount of information on Raveners, in particular Thassilonian Raveners, who fed upon their own rune magic rather than souls.

>Cenotaph in the Holds of Belkzen, also very sparse notes, has made a connection between the rise of the Whispering Tyrant and his visit to this location however.