I think Clark is a good example of character who's co-workers were often utilized (some would argue over-utilized at times). Hal in the early days. I'd have liked to have seen more of Barry at work than we typically did. Lucius Fox served the role of an ordinary person not in the know once upon a time. I thought Vixen working and seeing employees of hers could be interesting.
I think co-workers make a decent way to have civilian (unknowing of secret identity) characters in the supporting cast. Hardly the only way, but a way. And it gives us a sense the heroes have lives outside of being heroes. Not the only way to accomplish that, of course, but it's nice.
So, what heroes would you like to see more of at work or have a supporting or tertiary cast made up of their co-workers? Are there any heroes you would give jobs for that purpose, and who and what jobs?