Well, there could be several possibilities. RC might have been broken, or it could have been taken by another character. Or perhaps it was just put away and forgotten about.
I think RC in Toy Story might have had some kind of adventure or mishap that we weren't shown. Maybe it ended up in a hidden place and was waiting to be found again.
Maybe RC got lost or was misplaced. It's hard to say for sure without more context.
Slinky had a relatively minor role. He was still part of the gang but didn't have a major storyline or significant events.
In the end of Toy Story 2, Woody realizes his true place is with Andy and the gang. They all come back home safe and sound, and it's a feel-good moment. The movie ends on a positive note, leaving viewers with a smile.
The ending of Toy Story 3 sees Andy making the decision to part with his toys for the sake of giving them a new life and joy with Bonnie. The toys have one last adventure together before this touching farewell. It's a very emotional and fulfilling conclusion to the story.
Slinky had some adventures with the other toys but remained a loyal and helpful friend throughout the movie.
The toys found new meanings and adventures. Woody decided to stay with Bo Peep and help other lost toys.
Sid was kind of a troublemaker, but in the end, he learned his lesson and changed his ways a bit.
Andy doesn't have a major role in Toy Story 4. He's grown up and given his toys away, including Woody, at the start of the movie.
Lotso ended up being left behind at the daycare. He didn't have a happy ending like some of the other toys.
Slinky had some adventures and played an important role in helping Woody and the other toys. He was always there for his friends.
After the events of the first Toy Story, Sid's story is left open-ended. It's possible he learned to be more kind and respectful of toys and changed his ways.