I have about everything. For most you can go to their site to see what is showing.
Prime has some good stuff, but it is FULL of garbage. Tons of it. And they have a bad habit of showing you stuff in their list that is not free mixed in with stuff that is.
HBO Max has TONS of good stuff from new to old. It includes no live channels so take that into consideration. It also ignores a lot of prior HBO content that they don't feel fits their image anymore.
Paramount+ is very similar and is a must if you like CBS shows or Star Trek (also the Yellowstone prequel 1883 is only on there going forward). They do include your local CBS, CBS News, and a bunch of other "live" channels. They are mostly preprogrammed things like a channel just for SpongeBob ot one for Classic TV (showing The Love Boat right now).
I watch more Peacock than the others due to them having SyFy and WWE but they also have a lot of newer movies (The Northman is on there right for example). They also have a live selection of channels but oddly not your local NBC. It is all preprogrammed stuff like WWE, random movies, true crime, etc with a few news headline channels thrown in.
Hulu and Netflix have fallen by the wayside for me, I rarely watch them. But I do catch a lot of Disney+ for the Star Wars content.
ESPN+ (part of the Disney-Hulu-ESPN+ plus package Verizon gives me) is actually really good. It doesn't necessarily give you the live channels of ESPN/2/U/SEC/etc but it does have a lot of live ESPN3 and ESPN+ stuff as well as replays and back catalogue of a lot of their shows.
Discovery+ is my wife's thing. I occasionally watch it but not much. It has most of Discovery various channels stuff on it, but no live channels and sometimes it is months or longer before stuff shown live becomes available. It will be rolled into HBO Max at some point.
AMC+ is actually garbage. There is so little on it worth watching that I hate I spent what I did, which was like $20 for a year. I will not be resubscribing once my year is up and I would have cancelled if they refunded anything.
Curiosity Stream is absolutely fantastic if you like Documentaries.
BTW. If you are looking for a particular show, go to JustWatch.com and search for it. It will tell you what service has it. And I suggest rotating services if you are only going to have 1 or 2. See what is on and get the ones you like each month or two.
EDIT: Sitting here not reading the FREE part like an idiot. PlutoTV, Roku TV, Stirr, NewsOn, Peacock has a free tier with commercials. Plex, Tubi, Vudu.