I've kept up to date with the movies from the MCU, but I am grossly out of date with the TV series, of which I think there is only Agent Carter (not as relevant for the movies I think, besides that scene in Captain America 2), and S.H.I.E.L.D. (which from what I've seen seems more relevant, with Inhumans coming in phase 3).
I've gained what I can from this answer. But I can't tell which of the episodes listed are relevant to the movies (clearly, it seems that none are essential), and which movies are relevant to the episodes.
So which episodes are related?