Retro-bit, Retro Fighters, and Krikzz are a few more manufacturers I can think of making controllers with original ports.

In particular, Retro-bit’s Saturn Pro pad is…interesting, let’s say. I have also used Retro Fighters Striker Dreamcast pads - they’re quite nice.

In yonder days, a few companies like ASCII and Hori come up a lot for reliable stuff.