For eurorack format Serge modules just use a eurorack case and power… nothing special needed.
For 4U Serge there is the Random Source kit, as well as kits and built options from Elby, STS (pricey!), Konstant Lab, and Loudest Warning. Random Source also just released powered boats recently, with small switching supplies built right in.
The 4U stuff is also +/-12v, so you could use any eurorack supply with the proper distribution cables/board as well.
Edit to add — Serge has historically been DIY. So there is not much in the prebuilt category for 4U period…