Is there a script or something I can throw into an addon that will cap my fps to 30 if in raid, and 60 if is not in raid?
Why in the world would you want to?
Thermal control on a laptop, for one thing.
Throttling it back ahead of time can keep the thing from reaching thermal throttlling limits at an inconvenient time.
The underlying code you’ll need is this:
SetCVar("maxfps", (IsInRaid() and 30 or 60), "scriptCVar")
You can put that in a macro or if you’ve got a personal addon, you can put it into some event or other (“GROUP_JOINED”, “GROUP_LEFT”, “GROUP_PARTY_UPDATE” seem like good candidates).