I am very content with my alliant signature visa, as it gives 2.5% on everything, still has an extended-warranty benefit, and has no international transaction fees.

There are a few downsides, specifically (a) no contactless chip in the credit card yet, (b) need to keep $1k on deposit and have at least one monthly deposit of any kind/amount (scheduled ACH for $10) to get the 2.5% rate, otherwise it's 1.5%, (c) minimum redemption $50, and (d) ACH processing is a little slow/awkward, so you probably want to pay a bit ahead of time. And generally the UX is a little rough etc, they are a small credit union and it's not super polished, but it's functional.

But yeah I'm tired of category gimmicks/etc, they are not usually worth it anymore. BOA Signature Visa has 3% on category of choice (online purchases or home improvement being the good ones) but it's only up to $2500 in spend per quarter, and they count the non-choice categories against your total bonus, so using it for gas/groceries costs you from the theoretical maximum of $75 total bonus per quarter. And they charge international transaction fees which completely negate the online purchase bonus for anything denominated in non-USD (at least it's not charging for international transactions in USD anymore). And they really screwed up on a fraud case that took CFPB intervention to fix - it turns out, the price of my dignity is apparently $75 a quarter.

The costco card has 4% on gas, which is good (especially when I had a nearby speedway I could buy beer at), but it doesn't cash out until the next calendar year (so you can wait up to 14 months for points) so I generally don't use that except for the end of the year (I'll wait 3-4 months, I won't wait 14). But I think this is emblematic of the problem - the costco card (and many other store cards) only gives 2% even in the store, so it's worse than the alliant, on top of the onerous cashout process! Even if you have a more typical 2%-on-everything card, the costco card is pretty much strictly worse because of the cashout. I mostly got it for the 2-year extended warranty, that was the value to me, but they dropped that benefit at the start of 2022, so, it's almost useless to me now.

Notionally I could use amex or something and try to make it my primary card I guess, but I'm not a business traveler, and the alliant is just mentally easier. 2.5% on everything if you keep the $1k in the account and set up a recurring monthly $10 ach transfer, done. No international transaction fees, what you see is what you pay (plus or minus actual currency conversion, which is unavoidable). Use it as your primary card and spend $2000 and you'll cross the $50 redemption threshold every month. Is fine.

The Amazon Prime card is also very good, 5% on all amazon purchases is good enough I'll make a special point of it. If you do most of your bigbox purchases there, it adds up quick. They also have very good cash-advance offers, right now it's 4% transfer fee and 2% APY for a year - but the cash advance pays off first, and new purchases continue to accrue interest at the full rate (25% or whatever), so, you want to lock the card while you're doing a cash advance, so you are also foregoing that 5% (really, 2.5% above the alliant) from amazon purchases, but, if you're mature with it, it's great for consolidating other debt or financing things that need to be done in cash.