Nobody else uses them much anymore?
I just bought some Samsung button top 18650's for my 2.5's, relegating them to home use for now, but RTD Vapor has the (less than well reviewed) vapecell button top 18350's in stock atm.
These are not true button tops, being somewhat over-long for our requirements, but usable nonetheless.
I use mostly 18350 flat tops for my p3's.
These are pretty much available for now, if not the highest quality, which at 7W is good enough.
This is where the p3 IQ feature really earns its keep.