Higher Tech Species: Lots of them, arguably.  The Imperial member species are this for most, if not all, of the Associated Worlds.  The elder races – which, despite the technical definition based on the information entropy of their communications, in practice means “significantly older than the oldest of the current galactic mainstream” – are this to everybody, although nearly all of them aren’t particularly active any more, and have, for example, retreated into a virtual civilization in their own “Happy Fun Ball” (for which read, the matrioshka brain about eighty light-years to nadir of the Cordai Gap).  And finally, of course, the Precursors, who would be this to everyone except that they’re simply Sufficiently Advanced Aliens.