Using the most common recent OSU uniform elements, there are 32 combinations.  

2 helmets (Silver + Black)

x 4 jerseys (Scarlet + White + Black + Gray)

x 4 pants  (Scarlet + White + Black + Gray) 

= 32.  This does not include one-offs like the 2017 wolfpacks and the ones from the early 2010s. 

Here is matrix of all of them.  Some are unique yet still very Buckeye, some are trainwrecks or way too similar to other red/black schools. 

Bonus at the bottom are some unique possibilities for The Game if they insist on alts.