Particl is still in alpha.
https://particl.io/
Safex doesn't have a market yet
https://safex.io/
Bitbay claims to be open source but has made strong efforts to make their variables hard to understand.
https://bitbay.market/
Syscoin's Blockmarket is not open source.
https://www.syscoin.org/
Openbazaar needs a working open source search
https://openbazaar.org/
Crypto agnostic & decentralized marketplace now! Preferrably with web-UI ;)
What do you think?