Any good simple sprite changing mods?

[Whoah]

So I was dicking around with some lesser known mods that do nothing but change the sprites of the weapons/enemies. But I was wondering if anyone knows of or has any mods that do nothing but change the sprites of the items and enemies in the game? Kind of in a similar vein to old 90's TC's, but no new levels, preferably. I don't really care about the age or obscurity, I just have a soft spot for simplistic mods like these. They can be for Doom, Doom 2, Heretic, Hexen, or Strife (if those exist).

I greatly appreciate any mods you can shoot my way!