2p kitchen table formats?

I'm still somewhat new to MtG, and have mainly played commander, along with a bit of modern which was a little too intense for me. What are some good formats to look into for kitchen table, 2 player mtg with my wife? Commander is great but tends to want a 4 player format.

Bear in mind we'd rather not buy new cards, but used cards and proxies are fine, got no major price constraints since I'm happy to print up a card if it's going to be too hard to find.