So, I've been gardening. Have a couple of inqs about to drop off and boost me up around 800+ in the next five or six months. Been really eyeballing the Amex Gold because I want a charge card that offers competitive points, but I have cards that are already "good enough" that have no annual fee like the Citi Costco card, or the Discover IT, or even my lowly Alliant 2% card.
So. I think I've decided that I'm going to wait until a 4% anywhere comes along that doesn't gouge me with an AF. The Amex Gold AF is pretty high when compared to where I am spending (I already get 2~10% back at grocery stores using my Alliant or SquareCash Cash Card, and 3% with Citi Costco card) and I don't have to "overcome" the limits of an annual fee first.
So yeah, I was browsing the forum here—I love reading about the latest card happenings—and I realized that hoping for the next good card is kind of a bad addiction that has me twitching to open a new card, so I'm putting off any desires for a new card for now until that 4% w/ 0 AF comes along. heh.
here we goooo haha who am i kidding, i guess i'm never opening a new credit card again 
I think you will be waiting a while, but, good luck!
I don't really see Amex Gold and Citi Costco as near-equivalents. I like them both, but use them for different things. In my case, I get a $100/year statement credit for Gold, so the AF I have to overcome is $150 instead of $250. Otherwise, I probably wouldn't keep it. YMMV.
The unlimited 3% AOD card is the probably the closest you're going to get to that. The other route is to get several 5% cards to cover your highest spend categories. The US Bank Cash + and Elan Max Cash are 2 that have 2 selectable 5% categories that you get to choose each quarter.
I have the AOD card and I'm working towards getting the 5% cards listed above.
This is definitely the place to keep a lookout for it, but a 4% card with no AF would be a bank's way of losing money on every sale but making up for it in volume. 
(It would be ruinously unprofitable without a big increase in interchange fees, and funny thing, banks like making money.)
As others have said, don't hold your breath for no AF and 4% back everywhere. Interchange fees are where most of the cashback comes from so 4% is already greater than that. There were 4% CB cards like the original Barclays Uber, but that was on dining, so they were hoping that "regular people" (who don't lurk here 
) who only have 1 or 2 daily driver cards would use the Uber card for non-dining and they'd be able to recoup. Since you're looking for a card where 4% back isn't anything special, users are going to have to subsidize it via AF or something else.
