Abacus supports Bitcoin (BTC) and Monero (XMR) for payments.
While it does use the traditional account wallet system (meaning you must first top up your account balance before making a purchase), they do support Multisig 2/3 payments – an option employed by some vendors.
Vendors with a significant amount of completed sales under their belts are afforded FE (finalize early) privileges. One of the interesting things.
Familiar UI, well organized, easy to navigate.