We have several tags in use for the rings used while swimming. Several have wiki entries that reference each other.

inner_tube - 1200 posts (technically refers to a tube for the interior of a tire, but it's never used in that context for any posts I've seen)
swim_ring - 941 posts
pool_float - 231 posts
life_ring - 106 posts
life_preserver - 67 posts
lifesaver - 25 posts
rubber_ring - 5 posts
pool_floaty - 4 posts

There may be others in use I didn't think of while searching. I'm not sure what would be the best to go about either cleaning or aliasing these.

I can see possibly making a distinction between the inflatables and the life ring/preserver, because the latter are general made of foam (although in art the difference is just the red & white striping or emergency-orange color).

Prior forum posts I found about this: topic #23780, topic #12781

flotation_device too. It has a list. Perhaps it could be the overarching tag.

Material shouldn't matter, provided it floats. I think the main distinction is intended use.

I think there are 3 categories, if someone might be doing a merge cleanup:

1. Safety devices. Wikipedia umbrellas them as (Personal) Flotation Devices. Safety orange or red/white stripes, designed to keep your head above water
2. Water toys, like swim rings or inflatable pretend rubber dinghies, for having a good time with. Often inflatable, regularly brightly colored and attractive.
3. Swim training gear, like pool floats (possibly covers therapeutic and re-training gear for folks with disabilities or injuries)

Reason: very distinct kinds of use, appearance, and purposes.

Beware Pokemon with in-built flotation devices (buizel family), or inflatable fursonas (I dare not ask)