Leonardo (Teenage Mutant Ninja Turtles 2012 TV series)
Garo/Garou (One Punch Man)
Practitioners of the Hercules Method (The Strange Talent of Luther Strode)
Touya Mochizuki (In Another World With My Smartphane)
Carol (OK K.O.! Let's Be Heroes)
Rando (Yu Yu Hakusho)
Chomp Kitty (Glitch Techs); via Power Ups
Marivel Armitage (Wild Arms 2)
Po (Kung Fu Panda)
Various unicorn ponies (My Little Pony: Friendship is Magic)
Roronoa Zoro (One Piece); via Foxfire Style
During his time in the Negative 10, Dr. Animo (Ben 10) was taught how to telepathically control animals by Clancy.
Danny Fenton/Phantom (Danny Phantom) has quickly learned a lot of techniques by first look and without even having training on his part, as he first learned to create a Ghost Shield seconds after his nemesis Vlad created one.
Son Goku (Dragon Ball series) learned how to use most of his abilities and techniques, such as his signature Kamehameha Wave, from others.