Hoping that if/when archfey warlocks get added in they get some special interaction with Aunty Ethel. Pretty sure hags are a category of fey. Someone can correct me on that if I'm wrong. She does have redcaps serving her though which are definitely fey.
Speaking of red caps would be neat if instead of quatsits or imps they were an option the archfey warlock could summon with pact of the chain.