I have the following:

Schwab 2% Visa -- going to end soon.

Skymiles Amex Platinum -- Long-time SM member but looking at other FF programs because of the rewards redemption problems.

Platinum Amex -- just got 6 months ago. Got two 50k points transfers so definitely worth the first year $450 fee.

Chase Sapphire Preferred -- just got it and working on the $3000 spend.

Citi AA Amex -- got it almost a year ago, with the 75k AA miles.

Logical choice right off is the Skymiles Amex Platinum. Already in the process of doing a status match challenge with CO.

Citi AA Amex is another candidate buy my AA balance is over 85k, not enough for redemption. For now, probably going to concentrate on CO/AA and Star Alliance for getting status and miles. But without a card it would be hard to keep the 85k AA miles active with minimal purchases here and there.
Plus I would need an Amex to use at Costco once I get rid of the Platinum Amex.

The other wrinkle is that with Schwab going away, I was looking at replacing and one candidate would be the Fido Amex. Other choice would be Capital One Cash or Venture with 1.5 or 2% rewards.