Anon's Mod Recommendations

MUSIC MODS:

FOR CRISPY DOOM AND GZDOOM ONLY:
Roland SC-55 Music Packs: all the original Doom 1, Doom 2, and Final Doom music recorded in free lossless audio codec (FLAC) on an actual Roland synthesizer, just like the one Bobby Prince used to compose the original Doom and Duke 3D music! Download the boosted FLAC versions
> http://sc55.duke4.net/games.php#doom
To use in GZDoom, simply load the .zips like you would any other mod.
To use in Crispy Doom: See pic related. Unzip the files in your music-packs folder (to find the music-packs folder, type %appdata% in your start menu and open the crispy-doom folder). Put Doom 1 music in a folder called doom1-music, TNT's music in a folder called tnt-music, and so on. Download the configuration files on the right side of the page and put those directly in the music-packs folder.

For Plutonia music, use Jimmy's MIDIs!
> http://jamespaddockmusic.com/doom/plutonia-midi-pack/


MUSIC MODS continued:

FOR GZDOOM ONLY:
IDKFAv2 (Doom 1's original music, performed by Andrew Hulshult)
> https://www.youtube.com/watch?v=AGK1dr-Ql0w

Doom Metal Vol 5 (music for Doom 1 and Doom 2)
> https://www.moddb.com/mods/brutal-doom/downloads/doom-metal-soundtrack-mod-volume-5

Now That's What I Call MIDI (800 songs converted into MIDI)
> https://forum.zdoom.org/viewtopic.php?f=46&t=54096

FOR ALL SOURCE PORTS:
To use Now That's What I Call MIDI, or any MIDIs, to their fullest potential, download a MIDI player like VirtualMIDISynth, and download some soundfonts to play the MIDIs with.

Some soundfonts to play with:
Airfont380 (very good metal soundfont)
Touhou / SGM v2.01 (other metal soundfonts to try)
Mysung Kite (1 gig, very big, very good quality sounds. Sounds great with Eviternity's Heaven MIDIs, for example)
SC-55 (the original soundfont Doom's music was made in. Use if your source port cannot run the FLAC music packs, or to play with other 1990's megawads)
Microsoft GS Wavetable Synth soundfont (the default Windows MIDI-player soundfont, test it with some old-school megawads, sounds good with Hell Revealed MIDIs for example)
8-bit NES (fun to use this while playing D4V in Chocolate or Crispy Doom)
GZDoom's soundfont (comes with GZDoom; another soundfont to test out while playing classic WADs)




AESTHETIC MODS:

VANILLA-COMPATIBLE (works with all source ports, including Chocolate Doom):
Vanilla Doom Smooth Weapons
> (don't use this with custom maps with custom monsters or game will crash)
> https://www.doomworld.com/forum/topic/102462-vanilla-doom-smooth-weapons/
Per Kristian's Hi-Res Doom Sound Effects
> https://www.perkristian.net/game_doom-sfx.shtml
Doom Minor Sprite Fixing Project
> https://www.doomworld.com/forum/topic/62403-doom-2-minor-sprite-fixing-project-v19-release-updated-12718/

GZDOOM:
Brightmaps Plus
> https://forum.zdoom.org/viewtopic.php?f=46&t=64299
Smooth Weapons Enhanced
> https://forum.zdoom.org/viewtopic.php?t=32628
Sound Caulking
> https://www.doomworld.com/forum/topic/71133-sound-caulking-now-on-idgames/
Bolognese Gore mod unofficial update (fixes arch-vile bug)
> https://www.moddb.com/mods/brutal-doom/addons/bbgorenew
Simple Motion Blur
> https://forum.zdoom.org/viewtopic.php?f=103&t=62772
SpriteShadows
> https://forum.zdoom.org/viewtopic.php?t=54992
Steve's Flashlight Mod
> https://forum.zdoom.org/viewtopic.php?t=59429
Tilt++
> https://forum.zdoom.org/viewtopic.php?t=55413
Weapon Sway
> https://forum.zdoom.org/viewtopic.php?f=46&t=62634
Nostalgic Secret Sounds
> https://forum.zdoom.org/viewtopic.php?f=46&t=58283
Shader Tools / Bloom Boost
> https://forum.zdoom.org/viewtopic.php?f=103&t=59289
Fullscreen Statusbar Mod
> https://forum.zdoom.org/viewtopic.php?f=46&t=63863

Load these mods with a LOWER priority than the WAD you are playing with, so that the WADs custom sounds will over-ride any custom sounds you add (load the custom map last).
Generally speaking, don't use these custom weapon sprites mods with WADs that have their own custom weapons, and don't use spritefix or Brightmaps Plus's sprite mods with WADs that use custom monsters.
>How do I know if the WAD I'm playing has its own custom weapons?
Open it up without any mods, start the first level, type IDFA, and shoot every one of the different weapons.
>How do I know if the WAD I'm playing has its own custom monsters or sprites?
This is more tedious, but worth it. Download Slade, and open up the WAD using Slade, and skim through the graphics. Click on "Type" to organize all the files by type, click on the top of the list of graphics, and press Page Down twice, click the center of the page once, press page down twice, and so forth. This is a more thorough way of checking if the WAD has custom sprites compared to just pressing page down repeatedly. Skip over all the Flat Graphics as those will not matter. Also, the SS and Commander Keen are usually the first to be changed/removed, so on the bottom of the page, use the search feature - type "SS" or "KEEN" and see if there are any new monsters.