I think you can do the Deimoses and Sanfords sprites from 5.5 and 6.5 . Madness Project Nexus (1 and 2) sprites would be awesome. You also could add more zombie sprites, scrapface and scientists. Custom sprites would be cool too. I think the Relegard guy did a good list of sprites that you can make. Also, good luck!
Relegard
Here have some ideas (you don't have to do everything just giving you some ideas for you to do : ) HEY FAU17Y, START THE LIST
Fau17y:*thumbs up*
IDEALIST.exe
MAG freyr form realm 4
concrete golem from realm 5
gangly ones from madness 11(tricky skelly bois)
AAHW MAG from PN2
MAG agent v4-5 and 6(ducky)
Hank from mc5 and mc7 without his ninja attire and only his bandages with his metal jaw
g03lm, blackguard and ATP tower guard from PN2
Odium abominations and abominations from PN2
the different robots from PN2
the Hive and Hivelings from PN2
the weird ghoul from PN2 you found in the elevator with sanford and deimos
Zeds g03lm or MAGs
i think you haven't done a g03lm did you? (i refer to their classic PNC look)
church and jorge from PN2
your version of 2Bdamned
Phobos from PNC
some riot guards from PNC
Kelzad visor (put some extra detail too)
The chargers (made them have some detail to make them look less like a simple stick)
The Dragon sword (Krinkels remade it on stream)
The weapons that Krinkels has no updated in a while and weapons from madness interactive
g03lm Sleepwalkers and sleepwalkers from PN2
the prototype sleepwalker and sleepwalker from PNC
the asylum patients from PN2
IDEALIST.exe has ended