I'm sure that a huge number of people would appreciate American Express cards being supported by Garmin Pay. I stop by a grocery store by my house for a mid-run drink fairly regularly, and it'd be nice to not have to bring my card.
Adding the Barclay Uber Visa would also be helpful for me. I'm sure there are other's people would like to be added. I've already contacted both Barclay and Amex about this as well.