I can't think of any YC-funded companies that have slowly grown organically into modestly successful long-term businesses. Paul Graham made a comment somewhere that YC actually has no problem if the founders want to build a "lifestyle" business, and won't push for VC-backed moonshots if it's not in the founders' interests, but I just haven't heard of that outcome happening. It's possible I just don't know about them, though.

There have been several that sold for reasonably good totals without raising any funding, if that counts. For example, Clickpass sold for $1m, and raised no funding except YC's $20k.