Ethnography & ethnomethodology, as both being around for quite a while there must be theories/sub-fields which have developed out of these.
Coming from an interactionist point of view, I'm aware of social network theory (Milroy & Milroy, 1978) & Conversation Analysis, the sub field.
However, I'm looking for more theories/sub-fields to really drive my point about it being a useful method historically, and still is useful.
This is primarily from social sciences, such as anthropology, sociology, linguistics etc. etc.
Any suggestions/guidance are greatly appreciated.