I spent about a month looking into various controllers and checking the midi specs vs the OT midi specs. I ended up getting the Quneo controller. It’s pretty mind blowing what you can do with it and it’s taken the OT to the next level for me.
It’s USB only on the Quneo itself, but they make a little $45 MIDI 5 pin in/out box for it too.
It’s not going to be ideal for everyone, but you should really check it out. Plus, used ones go for pretty cheap!