I'm not sure if Roxxon will be part of any crossovers (though "crossover" isn't really the right term since it's all one big MCU anyway).
But yeah Roxxon is basically just "greedy corporation X" in the MCU.
I believe another example is the decommissioned oil tanker in IM3 and Killian's "reason to kill the POTUS that plays well on TV"
Reading my signature constitutes admission that I am correct. (Too late)

Roxxon is just Marvel's goto default morally dubious corporate entity.

Yes it was the episode 'Repairs' which had sort of a similar theme about someone being dragged to hell and moving around interdimensionally.

I think there was a mention of it in season 1 somewhere, not sure if there are any more apart from the episode before doctor strange came out.

Coulson also got gas once at a Roxxon gas station on the way to Thor's Hammer.

Coulson stopped a robbery at a Roxxon gas station, once (on the way to Thor's Hammer).

Roxxon was also involved heavily in both seasons of Agent Carter, and I believe it was referenced by Shield at one point.

Super hero and villain interaction(s), not crossover per say.