Moderator, Marriott Bonvoy & FlyerTalk Evangelist
Join Date: Oct 2002
Location: McKinney, TX, USA
Programs: United Silver; AA Plat/2MM; Marriott LT Titanium; Hilton Gold
Posts: 11,776
Unfortunately, AmEx stopped transferring points into Marriott Rewards a few years ago. Other than the Diner's Club card the OP mentioned, I don't know of any other cards.