Greg from LaserBear is currently selling his version of the 2-player, open source MickGuyver controller adapters he’s calling the “LaserBit”, These are 1ms USB controller adapters designed to work with the MiSTer FPGA project, however they should be compatible with basically all USB devices. You can purchase them as completed kits, or DIY versions for people looking to save some cash and have a fun soldering project:
I’ve been using these adapters for a long time and can vouch for how awesome they are. I’ve never had any issues and also confirmed the low latency during controller testing livestreams. Unless you specifically need light gun support for Genesis & SNES, there’s no reason to get SNAC; These are awesome and there’s no chance of the 1ms latency affecting any gameplay.