BIOS files for RetroArch cores and mednafen standalone.
Personally I use romvault for management. Get all your DAT files from whichever collections you prefer (I prefer No Intro so Dat-O-Matic is great for that). Then you put all your DATs in DATroot folder.
All your ROMs in TO SORT folder and then it does all the heavy lifting to make sure you have properly verified dumps of games.The great thing about RomVault is it will even properly sort all your ROMs into folders based on the DATs you provide. Super fast and fluid for organization.
Feel free to DM me if you have more questions after trying it out!.