I like rewards cards, and use them whenever I'm not meeting a Sign Up Bonus (SUB) for a new card, but the real money is in the SUBs. Consider if you have a decent 2% reward for anything you purchase and spend $2k a month on it. You would earn $120 over a 3 month period.
But if you just signed up for that card when the company was offering you a $500 reward if you spent $6k within 3 months, you would really be in great shape with an extra $650 in you pocket ($500 + $120). Fictitious example, but realist numbers.
So the trick is to find a great SUB on a card that has categories and other benefits that you can continue to use. To add to my example above, don't be afraid of cards with Annual Fees (AFs), because those cards often come with better SUBs and better benefits. Some of the cards we like have high AFs and when the AF hits the following year, we downgrade (or cancel) that card to a No Fee card, if we aren't getting continual benefit to outweigh the AF.
Finally, folks here will likely want to know if you have a business, or have a side hustle (babysit, tutor, lawn care, rental house, etc.) that could qualify as a business, mainly because Chase biz cards don't count against you personally. Chase has a rule that they won't allow you to get a new card if you have gotten 5 cards in the last 24 months, however their biz cards don't add to this count.
ETA: We will also need to get a feel for how much spend you could put on a card over 3 months and what kind of Amex you have.
This year (2021) I personally like the Amex Gold card:
- AMEX Gold Earn 60k MRs after $4k spend in 6 mos. (4x dine & grocery; 3x air; $120 dine credit; AF $250)
- The Gold will keep the $100 airline incidental credit thru Dec, and will add $10 monthly Uber/Eats credit soon.
If you have a suitable business, the Chase Ink Cash or Chase Ink Unlimited look good to me:
- Chase Ink Cash Biz Earn $750 after $7500 spend in 3 mos. (5x Office, Net, TV, Phone; 2x Gas, Dine No AF)
- Chase Ink Unlimited Biz Earn $750 after $7500 spend in 3 mos. (1.5x on everything; No AF)
The Discover card doesn't get mentioned much here, but it's a nice card to have especially during the first year:
- Discover It Earn $50 after first purchase in 3 months (5x rolling quarters, Doubled first year, No AF)