>>51416605absol (not even just because i personally like absol) or dragonite.
if you pick a speedster, the bots recognize you as the jungler. if you've got your ult before the regis as basically any junglemon it's probably over for the enemy team anyway but absol in particular with psycho cut and night slash is one of the best carries and can oneshot anything that isnt more than 4 levels over you. the ult with psycho cut can also tilt teamfights, and absol cannot be damaged while its ult animation is playing.
dragonite can ult half way across the map and steal objectives if your bot teammates can't group up. the ult can also bring you to goal zones quickly if you feel like you wont be able to walk there in a reasonable amount of time before you have to be somewhere. its ult recharges very fast as well. dragon dance + hyper beam is the usual combo (good for securing/stealing objectives from a safe distance, great damage dealer) but dragon dance + outrage is pretty good as well (good for melting objectives and winning 1v1s, dragonites boosted basic abilities still apply in outrage mode)
tldr; pick dragonite and snipe objectives like a coward to win or pick absol and remove the enemy team's mons from existence before they can kill your dumb bot teammates to win
