Does anyone know of any companies that makes after market heads, hands, and feet in 1/25th (or whatever the ###mm that would be? also where can I get some if so?
You’ll be hard pressed to find spare heads in 1/25. There are dozens in 54mm and 1/35, but none show up in a search at a prominent figure site. You might try finding a site that sells Jimmy Flintstone figures or stock up on race crew kits and Campus friends from Hasegawa and Tamiya. There might be some 1/25 Germans from Tamiya out there as well from the days of their 1/25 scale tanks.
Lemme know if ya find some heads…

^ what he said
I have given up the 1/25th idea.
Iv started sculpting figures in 120mm or 1/16th scale. Im still looking for heads, at the moment I need one, a male, any race, with a smug look on his face but not a happy look. So many heads I find the expressions are so seriously stupid that I cant imagine someone having a use for it.
For 1/24(1/25 to 1/24, the scale diff is so small that they are considered as one and the same) heads, you would need to do some head-chopping of mechanic, etc figures. Tamiya and Fujimi did/do a few sets of mechanics(race and civilian), drivers(race and civilian), race-queens, students, etc.
1/16 is tougher as most are military and thus stern faced.
actuially, im finding, for just aftermarket heads, for 1/16th/120mm the faces to be either in exaggerated poses like verlinden, OR in the most utterly stupid faces I have ever seen.