Here are some mod suggestions for Heretic and Hexen:

First, grab GZDoom or other sourceport (check the mods readme for compatibility):
https://zdoom.org/downloads

Gameplay mods
- Brutal Hexen/Heretic RPG: http://forum.zdoom.org/viewtopic.php?f=19&t=50697
- Descent Into Heresy (Quake in Heretic): https://www.moddb.com/mods/osjcs-quake-descent-into-heresy

"HD" textures/sprites
- Heretic: http://forum.drdteam.org/viewtopic.php?t=5304
- hexen_high_resolution_pack.pk3: http://www.moddb.com/games/hexen/addons/hexen-high-resolution-texture-pack
- Neural Upscaled Textures Pack for Heretic: https://www.doomworld.com/forum/topic/104990-heretic-neural-texture-pack
- Neural Upscaled Textures Pack for Hexen: https://www.doomworld.com/forum/topic/103770-hexen-neural-upscale/

Widescreen HUD/fixes
- Fullscreen Statusbar Mod: https://forum.zdoom.org/viewtopic.php?t=63863
- HR_HereticWidescreenv2.wad: http://www.moddb.com/games/heretic/addons/heretic-widescreen-hud
- hxwide11.wad (Hexen): https://forum.zdoom.org/viewtopic.php?f=46&t=54422&start=46&t=54422#p1074708
- widefist.wad (Hexen): http://forum.zdoom.org/viewtopic.php?f=19&t=31746

Music
- Music Covers by Xeotroid: http://forum.zdoom.org/viewtopic.php?f=19&t=48937

Sound/fx
- footsteps.pk3 by The Zombie Killer: http://forum.zdoom.org/viewtopic.php?f=37&t=35388

Thanks to:
Berzerk2002: Fullscreen Statusbar Mod
catbox_fugue: Neural Upscaled Textures for Heretic (Doomworld link)

these two upscale texture packs are fantastic, highly recommend if youre playing in gzdoom with 1080p or higher resolution

https://www.doomworld.com/forum/topic/104990-heretic-neural-texture-pack/
this is the original topic for heretic btw.

Hi, Do you have an idea on how to launch HD textures for Hexen when using Galaxy?

I use GZDoom and I don't want to use ZDL.

Thanks in advance.

You can load mods with these 3 methods:

1) Drag and drop
The easiest way is to drag and drop both the HEXEN.WAD and the pk3 file to the gzdoom.exe.
The problem with this method is that some wads or pk3 should be loaded in some order, depends on the mod.

2) Batch files
Create a batch with the instructions to load gzdoom, for example:
gzdoom.exe -iwad heretic.wad -file base\heretic_high_resolution_pack.pk3
or gzdoom.exe -iwad heretic.wad -file base\heretic_high_resolution_pack.pk3 mods\BrutalHereticRPG_V2.pk3

After the "-iwad" you write the name of the wad of Heretic (HERETIC.WAD), Hexen (HEXEN.WAD), Deathkings of the Dark Citadel (HEXDD.WAD), and after the "-file" you write the folder and name of the wad/pk3 of the mods.

3) Edit gzdoom.ini
Or, you can edit the gzdoom.ini file and search the autoload tag for the game (Heretic, Hexen, etc.), for example:

[heretic.shadow.Autoload]
Path=$PROGDIR/base/heretic-gui.pk3
Path=$PROGDIR/base/heretic-music-xeotroid.pk3
Path=$PROGDIR/base/HR_HereticWidescreenv2.wad
Path=$PROGDIR/base/footsteps.pk3
Path=$PROGDIR/base/heretic_high_resolution_pack.pk3 Thank you, I've edited the main post!

Make sure you also play the Faithless Trilogy for Heretic:

https://www.doomworld.com/cacowards/2020/best3/

-iwad heretic.wad

The method which consists in editing the ini file of GZDoom worked perfectly, I thank you for your help. :)

@TheBigCore Thanks I'll give it a try.

There is the HeXen "Serpent: Resurrection" mod for GZDooM: https://forum.zdoom.org/viewtopic.php?t=23024
It adds an RPG system (EXP points, shops, spells, etc), a new player class (Assassin), new maps, enemies, weapons etc
It comes with 3 flavors:
The main mod with a totally new campaign
A gameplay mod that adds the RPG system to HeXen/Deathkings (even a new hub map to buy Items)
Another gameplay mod that just adds the new wepons and the new player class in a more "vanilla" way.

While I haven't played the main mod (I hadn't a good PC at the time), the RPG gameplay mod for the base game was pretty fun. XD

Thanks, Hexen in RPG could be nice. ^_^

Here's another small mod for HeXen: Beyond Heretic that helps with properly displaying weapon animations in widescreen resolutions: https://forum.zdoom.org/viewtopic.php?t=37623

I tested this with GZDoom and it works 100% fine.

how about Hexen for Doom 3?
yes?

Hexen for doom3:
https://www.moddb.com/mods/hexen-edge-of-chaos/
http://www.hexenmod.com/
https://www.youtube.com/watch?v=Fz4PFYcYYac

youre welcome

The more recent EoC site was hexenmod.net, but it doesn't seem to exist any more.

https://web.archive.org/web/20190830031603/http://hexenmod.net/

Heh... So, people nowadays play only widescreen, ugly upscales and gamplay mutilating "mods". And nobody suggests normal WADs with additional episodes which are really precious in case of old Raven games.

I highly recommend this megawad (2020 Cacoward winner) made by Jimmy: https://www.doomworld.com/vb/thread/117375

Amusing.

Anyway, here's a bunch of my favorite Heretic and Hexen community-made episodes and levels:
(most of these require a limit-removing port like ZDoom or its derivatives (Zandronum, GZDoom, etc)

Curse of D'Sparil
https://www.doomworld.com/idgames/levels/heretic/Ports/curse
A 9-level episode for Heretic featuring superb level design, incredible architecture and high difficulty.

Heretic Treasure Chest
https://www.doomworld.com/idgames/levels/heretic/Ports/htchest
Another decent level pack. 3 episodes, 27 levels in total.

Thief - The Trail of the Arch-Heretic
https://www.doomworld.com/idgames/levels/heretic/Ports/njhthief
Excellent level design, atmospheric night city environment. This one is my favorite of the bunch. Inspired by the Thief series.

Faithless Trilogy
https://www.doomworld.com/forum/topic/117375-faithless-trilogy-beta-1a-released/
This year's best Heretic map pack, winner of the 2020 Cacowards: https://www.doomworld.com/cacowards/2020/best3/

Hexen - Curse of the Lost Gods (aka Curse of the Demon Lord)
https://www.doomworld.com/files/file/18817-hexen-curse-of-the-lost-gods/
A five-level Hexen episode from the maker of Curse of D'Sparil. Expect the same quality (and difficulty!) as in his previous masterpiece.

Ascension
https://forum.zdoom.org/viewtopic.php?f=19&t=63102
Not a Heretic or Hexen wad per se, this total conversion combines elements from both games and is set in the same universe (sort of). It features a huge, incredibly detailed world, an RPG system, numerous quests, NPCs, puzzles, new weapons and enemies, and many more.
Requires GZDoom and doom2.wad

More can be found here:
[url=https://doomwiki.org/wiki/Category:Heretic_WADs]https://doomwiki.org/wiki/Category:Heretic_WADs[/url]
https://www.doomworld.com/idgames/levels/heretic/
https://www.doomworld.com/idgames/levels/hexen/
http://i.iddqd.ru/viewtopic.php?t=58

Another graphic mod, it makes most object in the game real 3d but with the original aesthetic
https://www.moddb.com/mods/reikallhereticvoxels