harry potter - Why Could Young Tom Riddle Do Wandless Magic?

Why could young Tom Riddle do wandless magic? Dumbledore recounts the following memory to Harry via the Pensieve in Half-Blood Prince:

‘It’s ... it’s magic, what I can do?’

‘What is it that you can do?’

‘All sorts,’ breathed Riddle. A flush of excitement was rising up his neck into his hollow cheeks; he looked fevered. ‘I can make things move without touching them. I can make animals do what I want them to do, without training them. I can make bad things happen to people who annoy me. I can make them hurt if I want to.’

Half-Blood Prince - pages 253-254 - UK - chapter 13, The Secret Riddle

Are there canon examples of any other character(s) demonstrating such prodigious, purposeful, and focused magical skill at the mere age of eleven? What about wandless magic that is not accidental?

Answer

Intentional wandless magic? Sure; look at Lily flying up from the swing-set, and making the flower flex.

“Lily, don’t do it!” shrieked the elder of the two.
But the girl had let go of the swing at the very height of its arc and flown into the air, quite literally flown, launched herself skyward with a great shout of laughter, and instead of crumpling on the playground asphalt, she soared like a trapeze artist through the air, staying up far too long, landing far too lightly.

...

“But I’m fine,” said Lily, still giggling. “Tuney, look at this. Watch what I can do.” Petunia glanced around. The playground was deserted apart from themselves and, though the girls did not know it, Snape. Lily had picked up a fallen flower from the bush behind which Snape lurked. Petunia advanced, evidently torn between curiosity and disapproval. Lily waited until Petunia was near enough to have a clear view, then held out her palm. The flower sat there, opening and closing its petals, like some bizarre, many-lipped oyster.

Seems pretty intentional to me :) It's also implied that Snape caused the branch to fall, scaring Petunia, but that is on the edge of intention/unintentional magic, like Harry's Hair, flight up the wall, and vanishing of the glass; each was a response to an impulse, not a direct choice, like Lily's magic.

Harry was oppressed for what he did, and didn't pursue it, but it's likely that he could have done much more (specifically, at least as much as Tom Riddle could) had he tried; he just had enough negative reinforcement that he didn't try.