The ol' 5) and 6)

Copied over for archival purposes, with naughty words removed (which slightly defeats the purpose but whatever):

5) Tumblr pones

dufelbagofdraws.tumblr.com/
Does some pone, but it's spaced out, lot of anthro. Updates very often.

graphenescloset.tumblr.com/
Guy that ran that pretty much defunct rdisbestchub, and as expected focuses more on qt Doshu with a side of Flutter.

khaoskris.tumblr.com
Takes submissions based on pictures and does an excellent job catering to a wide variety of tastes.  Stories are usually shorter and straight to the point, but that's made up for in both quality and quantity.

blurbblob.tumblr.com/
AKA Fetish-the-menace, does good work.  Unsure if he's got stories on here that aren't in his pastebin.

askchubbydiamond.tumblr.com/
Draws, you guessed it, mostly chubby Diamond Tiara art. Does other pones in various sizes, too. Cartoony style.  Ded but occasionally does pone on http://ridiculouscake.tumblr.com/

redintravenous.tumblr.com/
Known in these parts as Red Ribbon's creator. Occasionally does fatpon stuff. Updates fairly frequently.

caloriescorner.tumblr.com/
Draws chub stuff, including poni. Fairly active.

trinityfate62.tumblr.com/
Great artist save for invisible noses among other minor things, but no pony stuff in quite a while. Still does chub stuff for other fandoms. Last active Jan 2016.

Dead (no activity in 12+ months):

rdisbestchub.tumblr.com/
Cute chubDash. Last updated June 2015.

the--pudgy-workshop.tumblr.com/
Gone. No updates in two years, dA account closed.

a-defenceless-pony.tumblr.com/
defenceless-pony-mod.tumblr.com/
Fat/fattening ponies. Abandoned in 2014. Threw a fit on FA about how they hated Season 3 so much(http://www.furaffinity.net/journal/5493117/) they didn't want to poni anymore.

ask-banana.tumblr.com/
Adorable comic featuring a fatponi, Banana Cream. Abandoned in 2013.



6) FA/DA
I should really just nuke this part, Derpibooru often gives you the source of such things and if any of these guys are still drawing it's probably not pone any more.

Given that these people could have stuff other than pone, you might as well search for them on (Derp/Pon)ibooru unless you're curious/into that sort of thing
Note that you'll also need to make an account to see nudity

http://www.furaffinity.net/user/chloridecull/
Writefriend who's doing a fat pon text adventure - check twitter for updates I guess.  Written stuff is pretty good, focuses more on the size of the pony than things being stuffed into holes.

http://trinity-fate62.deviantart.com/gallery/43620730
Big, round, soft and flabby ponies.  Occasionally noseless anthro.  Great coloring jobs and superior shading leads to pon looking even more pillow-like than most.

http://www.furaffinity.net/gallery/drumstickpony/
Draws round, possibly flabby pon, semi show accurate in terms of style.

http://pony-pudge.deviantart.com/
Pony Pudge's deviantart account.  Contains monochrome somewhat sketchy pon, requires a blood sacrifice of a couple cents for some DA points to spend, but takes suggestions for free.

http://www.furaffinity.net/user/sirmasterdufel/
Uses thinner lines, good at drawing pudge and jiggling.  Some of you probably know him from his Rarity or Applejack sequences.

Dufel occasionally streams at http://www.livestream.com/dufel
Check his tumblr like a frenetic zealot.

http://www.furaffinity.net/gallery/redribbon/
Big and cute pone abound.  Good at drawing squish.

http://www.furaffinity.net/gallery/calorie/
Resident artist from /mlp/.  Usually takes requests, half-way show accurate.

http://www.furaffinity.net/gallery/defenceless/
Good if you like expandy/bloaty pone, might have bonus appeal on top of fat pone due to situations and short stories.  Pones are usually fuzzy.  Ded ;_;7

http://www.furaffinity.net/gallery/fatpony/
Hit and miss, lots of GLORIOUS MOONBUTT and her GLORIOUS BUTT
Also bubblebutt Derpy for good measure

http://www.furaffinity.net/gallery/sagejackal/
The dead nor the living will ever know peace from this evil.  Go in for anthro pone pictures, get out as fast as possible.
Known as Revadiva or Revadiehard on Ponibooru

http://www.furaffinity.net/gallery/naughtyblush/
Pregnant grey and pink OC horse.  Only a few pictures.

http://eggo81194.deviantart.com/gallery/38100869
3DQT pone, kind of neat
Everything else is 3DPD

http://xniclord789x.deviantart.com/gallery/40761959
Pregnant pone.  Has other pregnant nonponies too (dirty casual 360nohooves).