Good point. HERE is a link to all the official PF2 nonlethal options. Those without access to Martial weapons (like my Alchemist) should be advised that there are only 4 legal options, not counting fists: the Juggling Club, the Nightstick, the Poi, and the Blowgun.
I'm thinking about the Blowgun, it honestly sucks but as an Alchemist maybe I can finagle some more utility out of it. The Nightstick and the Poi are probably the best of the four, but it's a pretty narrow range. Unfortunately a Sap is a Martial weapon, although if you have Martial proficiency the Whip is a solid choice.
EDIT: there is apparently a Water Bomb, but there is no way I'm wasting a formula on that.