There are a few mentions in various lore books of the Wild elves, such as This one. They are not encountered in the game oblivion though. The key thing to understand about the "wild elves" is that they are very far removed from the ancient ayleids that ruled Cyrodiil before the Alessian Empire. The wild elves are little more than savages, and any connection they had to ancient ayleid culture is as dead as the culture itself.
This pretty much covers it, though I would stipulate that we don't actually have any evidence that their connection to ancient Ayleid culture is dead. Mer are long lived, and while we have no information on
how long lived in the case of the Ayleids, I would put a conservative guess at at least 500 years average. Perhaps less, if we think they've been living like savages (though personally I'd place that at doubtful). Sorcerers live longer, and if they've got a Divayth Fyr hiding out it's entirely possible that there is a direct link to the original culture. Note that this is unlikely: wizards that powerful are also usually renowned.
One other point: Just personal speculation, but Valenwood is probably the best bet for harboring culturally and racially pure Ayleid 'tribes'. We know, at least, that the Bosmer welcomed their elven cousins as refugees from the pressure of the Alessian Order, though they fled to other elven settlements, such as High Rock, as well. Jungle's pretty good for disappearing into, and keeping hidden from the rest of the world ('Ayleid' does actually mean something like 'hidden', doesn't it? Check me on this, I don't remember if I saw this in actual lore or discussion.) for long periods of time. Frankly, they should be in Cyrodiil as well, but then Cyrodiil
should be thick jungle as well instead of hardwood forest. Chalk it up to gameplay limitation (i.e. the misalignment of our expectations for Oblivion and Beth's objectives).
A compilation of links for further reading:
http://www.imperial-library.info/content/oblivion-wild-elves
http://www.imperial-library.info/content/pocket-guide-empire-third-edition-wild-remain-valenwood
http://www.imperial-library.info/content/oblivion-last-king-ayleids - Illustrates that Ayleid withdrawal from Cyrodiil was a gradual thing and the Alessian Order's part in accelerating that retreat.