This is the monsters from ShadowCaster (Raven Software) that are randomized with the regular monsters in Heretic with Random Spawners. There is over fourty monsters added. It is for Heretic only and works for most Heretic mods too and is made for G/ZDoom and Zandronum. There is also optional files to combine HeXen, Witchaven and Dungeons&Dragons;: Slayer/Deathkeep monsters as well as other optional files for Wrath of Cronos & Brutal Heretic RPG support.
This is just a simple mod that randomizes ShadowCaster monsters into Heretic. Each enemy placement in Heretic has been replaced with a randomspawner. There is forty-four or so added monsters in total. I am a big fan of ShadowCaster and the Raven Software style sprites are so visually similar to Heretic that I think they fit. I tried to find other mods that used the sprites and there were only a few here and there and not the entire bestiary. There is also support for Wrath of Cronos or Brutal Heretic RPG as an option.
Shadowcaster...that one was a challenging game to me as a kid but I did manage to finish it.