It's not just Robinhood, IB and WeBull have also suspended GME. Schwab lets me get all the way to confirming an order, but I'm not spending $370 on a share of GME to confirm if it will go through haha. IB/WeBull/Schwab seem to still allow AMC/NOK/BB.

Those are the brokerages I use, can't check in the others.