Seeking GIM restriction suggestions

Hello! A friend and I are currently looking into doing a weird GIM run at some point in the future but we are currently running into the issue of figuring out a fun gimmick/limitation to play around with. So I come here to humbly ask for suggestions we might have missed.

Our current considerations were the following:

-Global Trade Ironman: Each of us is region-locked and must use the bank to access items unavailable in your region (Possibly requiring you to trade items of equal value exclusive to your own region with the other player to obtain them)

-TCG-locked (seems popular lately)

Looking forward to hearing from some of you!