Perhaps this has been discussed over the years and perhaps it is obvious, but there are a fair few hints in ED that relate to Royle Family universe.
The Grapes - I reckon this is Jim and Dave's local but obviously refered to as The Feathers.
Dave's mate 'Duckers' is Duffy in ED
Tommy is the old man (Ted) who sits alone is referenced by Jim a few times.
Beverley Macca who we never see, is possibly the bird who shags Joe in the toilets during the night he is DJ'ing at the pub. And evidently had huge tits and isn't exactly shy.
Dave in RF is Joe in ED - they both do dj'ing
Ken is Jim in terms of humour and sarcasm
Jean is possibly a friend of Nana's (Elsie) although much younger than Elsie is referenced in RF who eventually dies, but Nana always slagged her off for being nosey and bitchy. Which is what Jean is all about.
Ken's one liner repeated from RF of 'if It's the invisible man, tell him I can't see him'
I'm possibly missing a few more there.