AJCO: C_N (more commonly known as Cain) of the Deserters is excitable, friendly and dorky. He's rather out of place when compared to the more cynical S_K and the more, well, sensible Lartin.
AmazingPhil or Phil Lester on YouTube. He may be in his 30s, but he's more like a hyperactive child with a rampant imagination and endearing kind of clumsiness. Of course, we wouldn't want him any other way.
Channel Awesome and Blistered Thumbs have their fair share of keets.
As convention-goers can attest to, Doug Walker is a smiley, bouncy, hyper flirt who likes his glomps. His character also descends into grins a mile wide, running around excited and super-sonic Squee when he's enjoying himself.
Our favorite "sexy French space lumberjack", Benzaie. His catchphrase is yelping "BUT WAIT!", he's known to get into compromising positions with Spoony and had a sweet, violent, and hilarious rivalry with That Dude in the Suede, and he's prone to randomly cross-dressing. He's also really, really pretty. Benzaie seems to be the French example of this trope. And we love him for it.
Especially his crossover with Sad Panda, Masoko X, Welshy, and Mike J. He starts laughing hysterically and can't stop for over five minutes. In the end they have him cover his eyes and pretend he's crying so they can keep filming.
Lewis Lovhaug is apparently this in Real Life, according to Spoony, who said that during the filming for Kickassia he still had energy for shooting videos after a day in the desert outside Reno, while Spoony himself was wiped out.
Every Angry Joe Show is a continuous 20 minutes adrenaline rush. His personal favorite games are dancing games.
Cream Heroes: Lulu fits this to a T. He absolutely loves chasing toys around and is never too far away when food is involved. Then Dodo comes along and makes him look positively peaceful with some of his antics. Naturally, the two are good friends and partners in crime.
DSBT InsaniT: Blake is very expressive and talkative.
Zack from Echo Chamber is enthusiastic, chipper, and loud.
1-Up in the 20X6 universe of Homestar Runner. This also applies a little bit to present-day counterpart Homestar Runner himself, although he is more of a Cloud Cuckoolander and most any behavior he exhibits that falls under this trope is as a result of it.
Keiji Tanaka of Survival of the Fittest, whilst not exactly small, fits the rest of the criteria for Keetness to an absolute "T". Chris Davidson and Albert Lions of v4 are this as well.
Barbie: Life in the Dreamhouse has Ken, who even goes as far as having a disorder that causes him to squeal and FAINT at the sight of overtly cute things.