What “props” can you use in an active older adult water exercise class that would make the participants have more fun?

Noodles are simple and cheap. Sometimes plastic balls (children’s balls) can be used for resistance. When I taught water fitness my classes loved the webbed gloves for more intensity. If they put on belts you can do deep water aerobics even with those who do not swim well since the belts keep the students supported.
Back in the day (before all this amazing water tools) we used things like milk or OJ jugs (sealed), rubber 4-square balls and we even tried tubing and dynabands. They did not last long as the pools were chlorinated and the chlorine took it’s toll!