my latest is kayle, i'm probably better with her than i am most characters so i know how to play her decently well.
my build was as follows: madreds bloodrazer, chyrstal sceptar, sorcery boots, nashors tooth, frozen heart, and guinsoo's rageblade.
summoners: heal, ignite
ap, att. sp, armor runes
with heal, ignite and kayles ult + heal at max CDR i didnt need buffs but with was a close call and the max CDR was a must
hextech gunblade may be a better option than guinsoo's rageblade but idk thats just how i built her
so if you have a good story of how you killed baron by yourself using some off the wall champion feel free to share it