Precursors: Played straight – but not completely. The species generally referred to as the Precursors got the name for having some of the most extensive local influence, and for being the species that made the eldrae, but in practice, they’re most notable for (a) being one of the oldest (but not the oldest) of the elder races, and (b) being not around any more, almost certainly through self-induced war-extinction. Certainly not the first race to ever gain sophoncy in the galaxy; there’s plenty of evidence around of older species yet.
(Also, reputedly, near-solipsists who were literally incapable of conceiving that another entity’s opinion might actually matter, short of a major mental break. This might just have something to do with why they aren’t around any more.)