Back in pathfinder 1e, one of my favorite characters was a grenadier alchemist who used a bunch of those neat special arrows from the alchemy manual, and I'd love to see those make a return.
At first, I kind of imagined it would work like the 1e explosive missile feat, but after seeing alchemical shot (a feat I absolutely hope to see make it to the alchemist as well as the gunslinger) provide a really neat way of handling the mixing of bombs and strikes on the fly, I think making alchemical bomb ammo as actual gear that anyone can use would actually be a cool addition to the equipment section, not to mention a really cool new tool for alchemists.