You can manage up to 5000 domains at a time with the Dynadot control panel (1.Viewing)

The only other marketplace where you can do that is godaddy

Other than at godaddy I don't know anyone else that does that.

Godaddy does bulk tools extraordinarily well.

I have no problem managing more domains than that at Baremetal.

You can't match godaddy bulk tools, you can import export, do virtually anything in bulk including exporting with the transfer codes.

I have yet to see ANY registrar that can touch the godaddy bulk tools, it's the one thing they do extraordinarily well.

Yeah, I can't get bulk auth codes from Baremetal's interface. Then again, I have no need or motivation to move anything away in bulk, and its kind of a safety feature that they all can't be moved in fell swoop. And if I asked Baremetal's support for them in bulk, I know they would simply email them to me if I asked.