I've forgotten the download Apple ID I bought one app and one app bundle on the App Store, but I forget what Appel ID I used.

I've tried several Apple IDs to find it, but can't find the one. I remember I connected it to my bank card, if that's useful?  

How can I find it?
First find the transaction on your bank account transactions summary. Then contact Apple and ask them to reference which Apple ID made that transaction.

They may not give you the full email, but maybe the first/last few characters may give you a hint.

Best of luck!