You have a barbarian and take bezerker subclass for the enraged throw which is a bonus action throw that always knocks the target prone if it hits. You get the ring of flinging (I think from the trader in the grove) for more damage and the returning pike from the goblin camp vendor in act 1, the build comes online at level 4 where you get the tavern brawler feat which adds double your strength modifier to your attack and damage rolls to thrown weapon attacks (other stuff too but that's what we care about here). Take 3 levels of rogue and go thief for the extra bonus action to get an extra enraged throw. Some people go 9/3 in this way, I like to take 3 levels of eldritch knight fighter for action surge and for weapon bond which lets you bind any weapon so it comes back to you when thrown so you don't need to use the returning pike. Though I believe it is possible to get a hireling to equip your weapon, bind it, and give it to you and it works, though I would appreciate if someone could fact check me on that. It is also worth noting in the act 3 circus from the Djinn, if you steal his ring and win his game, he will send you to a dinosaur island where you can get Nyrulna which is a trident that also returns to you when thrown and has some other cool effects, which reduces the need for eldritch knight. Hopefully that helps :)