This is a good series and most of them are worth playing. I'll write a bit on what I think of each one and the following is just my opinion.
The original trilogy is fantastic. R&C1 is a bit dated, but R&C2 is where the series peaked as far as I'm concerned. All three should be experienced.
Deadlocked/Gladiator changes it up by being essentially a collection of arena based challenges with a story. I wasn't a huge fan of this idea, but still found the game very fun. The ps3 remaster has some heavy visual glitching, especially in cutscenes, but it's worth playing.
The Future trilogy and Nexus are alright. Tools of Destruction doesn't have trophy support. Quest for Booty doesn't either and is incredibly short. Crack in Time is the best one out of them. They're all good games and all four are worth playing, but I'd put experiencing the original trilogy and perhaps even Deadlocked above these.
All 4 One is another change up. This game is a simplified, co-op multiplayer focused take on the franchise. It's not bad, especially with friends to play with, but I wouldn't worry about missing out on this one.
Full Frontal Assault/Q-Force is yet another oddball, being a tower defense game with a large focus on multiplayer, but also a short campaign to play through. It's more true to the series formula than the earlier All 4 One I think, but despite this it's the game I enjoyed the least. I don't think it's completely unfun, but I'd put this at the bottom.
The PS4 movie tie-in game, the reboot of R&C1, is a mixed bag for me. The gameplay is very good, but a sizable chunk from R&C1 has been cut, and the changes to characters and tone are not for the better. Hate using this term but when comparing this to the game it's supposed to be reimagining, it feels soulless. But again, plays good, so worth it for that. Under the original trilogy, Deadlocked, and Future+Nexus, but above All 4 One and Full Frontal Assault.