perhaps the befaco instrument interface?

not seen any diy modules like batumi to be honest

maybe this: https://pushermanproductions.com/product/void-modular-dual-adsr-12hp-pcb-black-gold-aluminium-panel/ for the adsr???

"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia

Utility modules are the dull polish that makes the shiny modules actually shine!!!

sound sources < sound modifiers < modulation sources < utilities