Milwaukee makes a Water Transfer pump that is battery operated .. I bought one for my son so when and if he needs to add water to the fresh water tank no lifting .. it's a great tool ... Milwaukee M18 Transfer Pump - No Charger, No Battery, Bare Tool Only
Ryobi combo pump like the others have. Makes inflating mattresses easy. I have the hybrid fan. Haven't used it for camping , but have used it for other things. As a hybrid I can plug in or run battery mode as needed. I did get a combo fan light that uses that stereo plug. Have yet to try that too.
I've used the pump for helping along fires too.
Most accessories in the 18v flavor? I think it's still Makita. However Ryobi has a lot of consumer grade items at a very very good price. I have DeWalt Ridgid and Ryobi. At first the Ryobi was just for a cheap set to toss around . But then it was the hedge trimmer , string trimmer, chain saw, drain auger, inflator.... Heck I even have the soldering iron.