First of all we have Animals which are thought extinct but may still exist:
The most likely (of the better known species) are the Thylacine, Eastern Cougar, the Ivory Billed Woodpecker and Steller’s Sea Cow. (on this last I admit I am just projecting hope onto a few unverified sightings).
Then we have three which have considerable local native background info:
Yeti (I think it’s just a unknown bear species)
Nandi Bear ( maybe a large hyena variant?)
Orang Pendek
A WTF goes to Steller’s Sea Ape, which I am sure was some sort of unknown animal. Likely extinct. Maybe a large mink like those recenlyt gone extinct off the East coast of the USA.
I googled it and this thing was almost certainly some type of known pinniped, simply misidentified as an ape. Could be some kind of seal or sealion or walrus, but look at the description.
I don’t have a list at my fingertips (Colibri probably does) but I think there are at least a dozen species of birds known from museum specimens that have been thought extinct for a century or more, and in the past few years have been confirmed to be still alive. In at least one case, a bird thought extinct for decades was found to be so locally abundant that it was locally hunted. So any list containing presumed extinct species wold certainly carry quite a few that still exist.
A few years ago, a Jacana was spotted making one of its rare appearances in North America by a visiting golfer in Arizona. He brought it to the attention of the groundskeeper who said Oh, that’s been here for a couple of years.
Well, he could get sea monkey eggs from an 18th Century edition of the Johnson Smith catalog, though Saturday Night Specials were still in the future, but something closely related to an animal having a name was transformed with the addition of the magical Steller’s to the front of its name, like Steller’s Sea Monkey.
Wasn’t there a documented sighting of the Ivory-Billed Woodpecker about five or so years ago? I seem to recall it being all over the news for a day or two.
From an Australian perspective, it is possible there is a small population of the Tasmanian Tiger still being alive. Tasmania still has large tracts of untouched wilderness including dense forest areas in rough mountainous areas. I personally suspect they are extinct but there is slim chance.
Other Australian cryptids, the Yowie and the Bunyip, totally fictional.
I’ve long been fascinated by the Tasmanian Tiger (Thylacine). I consider – with great regret – that it’s almost certainly gone. I reckon the situation such that if the species had survived, it would have been re-found by now.
There have been reports in quite recent times from remote highland areas of West (Indonesian) New Guinea, of an alleged carnivorous mammal in those regions, known to the tribesmen as the “dobsenga”: from their descriptions, it sounds a lot like the thylacine. I’d be ready to put more hope in undiscovered creatures in New Guinea: parts of the island are still relatively little-known to science.
I don’t think confirmed real animals that we have specimens of and even video of count as cryptids, even if they are extinct. There is no doubt they were real(the prefix gives it away).
Point seen, if one is applying strict linguistic rigour; but the cryptozoological “fancy” / sphere of interest in general, interests itself in animals which definitely once existed, and about whose being extinct, some doubt is entertained (e.g. Thylacine, Ivory-Billed Woodpecker, New Zealand Moa [some of the smaller kinds]). Students of cryptozoology are, in my experience, usually as curious about creatures in this category, as about those never catalogued by science; whether – in language-purist terms – they should be, or not !
There have been on SDMB over the years, quite a number of threads about, or touching on, the Ivory-Billed Woodpecker – type in “woodpecker” on the Search function. I happened on one very recently, in which a poster was asserting that he knew – did not just suspect – that he’d had a good sighting of an ivory-bill, not many years ago (was not photographically equipped when it occurred). This is post #20 on the thread “Rarest animal you’ve seen in the wild?”, IMHO sub-forum, commences 04-13-2007.
What I’m remembering was a camera set up in the woods somewhere that clearly recorded an ivory-billed woodpecker, and it made a bit of a splash in the news. I could be misremembering, though.