can anybody tell me what a custom belt card is

what exactly is that? do you mean custom belt? the item?

should be in rapid threads and it lets people with 20k-50k qi have custom belt names

I believe he means the Custom Belt TITLE.

Noob, a Custom Belt Title is something you are able to buy when you have 20,000 QI(QI, ammount of games played), if you have that Title, you are able to put any word(s) in front of "Belt" and people will be able to see it ingame. You can also change the colors of the Title by typing ^ and then two numbers.

thank you

I don't think there's a custom card.But i think you mean the custom belt title, once you reach custom belt you get to change your belts name.And that's all the things with custom and Toribash.

Use the beginners sanctuary in future.