I have a couple of slides, a small dome monkey bar climber, sandbox and water table, a tent/stage I made out of a couple old curtains, and some ride-on toys that I rotate in and out of the garage. I also have a bin of cars, a bin of play dishes, a bag of blocks and a bin of books (mostly board books so they can stand up to a little dirt and moisture.)
The bins of smaller toys I keep in a plastic storage cabinet like this:
https://www.amazon.com/Rubbermaid-Ou.../dp/B000L0CPPM
which has kept them dry and reasonably clean and bug free through a full year of seasons so far.
Sometimes I bring out art supplies, too, and let them really go at it since clean up outside is a bit easier, but I don't like to keep that out there for various reasons.