The two ladies are friends, and their relatable circumstances would make it only logical for Felicity to call her up for help.
If anybody has input that could be helpful to Felicity after losing Oliver to prison, it would have to be Iris.
Honestly, I’d be game to see Felicity just calling up Iris to vent.
The Arrow-verse may be comprised of many Earths, but there’s not so much distance on Earth-1 that shows like Arrow and The Flash can’t pull off quickie crossovers every now and then.