Haley: HEY! When's the last time either of you were the American Dragon? Well as the little troll girl currently filling the position, let me tell you it's stinkin' hard! I can't imagine doing it two more days let alone two more years. And to think about everything Jake's gone through; he's had to save magical creatures on a daily basis, lie to his own dad about who he is, say good-bye to the girl he loved, all to protect a mystical world that nobody knows about. He may be the American Dragon but he is also a 14 year old kid who just wanted a couple days off. If that makes him immature, fine, but self-serving? With all due respect to both of you, STEP OFF!!
Trixie suiting up in plate armor during "Siren Says" to face down a mind controlled Jake. Besides the fact she moves pretty fast in heavy armor (the suit alone would be about twenty kilograms (forty-four pounds), never mind the flail and round shield), she also holds her own fairly well and eventually gets the drop on Vikki.
Jonathan gets one in "The Long Weekend" and later in "Bite Father, Bite Son." The normally bumbling human dad fights to protect Jake from the Jersey Devil and vampires, respectively. He later helps save the day in the series finale as well.
The battles against the Dark Dragon in "Hong Kong Knights":
in the present, Jake, with some help from friends, both magical and Muggles (thus giving the Dark Dragon a Shut Up, Hannibal! before he could even talk), waltzed in his hideout, freed Lao Shi (who had been captured), captured Chang (courtesy of Trixie and Spud), and led him in the spot he needed for the Tooth Fairy to drop a few tons of bricks on him. And this time, they killed him (even if Chang would later bring him Back from the Dead).
#09, the Gorgons: two petrified and dumped in the Hudson (courtesy of Spud and Trixie), the third and last returned but got beat up and is still at large;
#08, the Octo-Puss: beaten back in its own dimension;
#07, the Hobgoblins: won every fight, and even hired a clan to fight the Huntsclan once;
#06, the Chimera: caught and sealed back into Rotwood's dreamscape where it belongs;
#05, the Kraken: tied up the one the Huntsclan sicked on him;
#04, the Huntsman: fought multiple times, always won, often in ridiculous ways (fire fart, anyone?). The whole Huntsclan was eventually destroyed by Rose;
#03, the Krylock: Jake went in its own dimension and had it poison itself;
#02, the Kelpie: beat up and sent back to the mermaid's jail;
#01, the Dark Dragon: fought thrice. The first time Jake escaped, the second time he orchestrated his death at the hands of the friggin' Tooth Fairy, and the third time helped Rose defeating him and sealed him away for a thousand years.
The twenty years younger version of the Huntsman in "Hero of the Hourglass" gets a few. Not only he gives Jake a desperate run for his money on his first mission, but after his voice changes he scares into submission the other Huntsclan apprentices who, until then, were treating him as a Butt Monkey.
Spud and Trixie outsmarting and defeating the Gorgons in "Bring It".