Nintendo 64 Cart Memory Battery:
CR2032
Nintendo Game Boy Advance Cart Battery:
CR1616
Nintendo Game Boy Cart Battery:
CR2025
Nintendo Game Boy Color Cart Battery:
CR2025
Nintendo SNES Cart Memory Battery:
CR2032
Nintendo NES Cart Memory Battery:
CR2032
Nintendo Game Cube Memory Battery:
CR2032
Sega Saturn:
CR2032
Sega Dreamcast:
2032 or LR2030 (NOT a CR2032 as it is not rechargeable)
Sega Dreamcast VMU:
CR2038 (Takes two of them)
SEGA CD Model 2 RAM Battery:
CR2016
I will add more as I think of them.