Where would you suggest I start reading Kitty/Rachel? Also do you know of any posts that list all comics where they interact?
I don’t know of any posts, but I do have some comics you should check out.
•Uncanny X-Men #141, which is Rachel’s first appearance.
•Uncanny X-Men #184 and onwards for a period of time.
•The original run of Excalibur, which I cannot recommend enough. It’s one of my all time favorite X titles, and it’s filled to the brim with Kitty/Rachel scenes.
•X-Men (2014) by Brian Wood. It has some shitty moments (cougcough John Sublime coughcough) but it also has a bit of Rachel and Kitty interacting.
•X-Men: The End, which is an AU of sorts that’s got a LOT of Rachel/Kitty moments. Chris Claremont actually confirmed that they’re married in this AU, and that Rachel is the mother of Kitty’s youngest children (who if you look carefully, have red hair).
It also looks like the new X-Men Gold series will have a bit of Rachel and Kitty moments, due to them both being on the team.