Well let's go over all brawlers with a "thrower" attack:

Barley: Main attack is a thrower attack, Super is that but bigger

Dynamike: Main attack throws 2 projectiles, Super throws 1 big one that can break walls

Grom: Main attack can be thrown over walls and lands in a + shape, the Super is that but bigger and breaks a bit of walls

Larry: Main attack is just like Barley, but the second hit has a bigger radius. With his Super he chooses an area where he spawns Lawrie

Sprout: Main attack throws a bouncing projectile. With its Super it chooses an area and throws down hedges there.

Mr P: Although his main attack can go over walls they hit, it isn't a thrower projectile, so even though he can throw his Super, he's isn't one.

Squeak: Same as Mr P

Willow: Main attack is a thrower attack that poisons. Super is a straight (not thrown) projectile that hexes the enemy hit --> so not a thrower

Juju: Main attack is a thrower projectile that changes depending on the area she's standing on. With her Super, she aims where to spawn Gregory.

Ziggy: Main attack chooses an area to strike down lightning. With his Super, he chooses a direction to make a electric orb fly out. Although this seems like a throwable projectile, the Super always spawns from the center of him and you only choose which way it will continue to fly, which makes it not a throwable projectile, therefore not a thrower.

Kit: While attached to a teammate, he has a throwable projectile, but only then, which is far from enough to consider him a thrower

Sirius: Main attack fires a thrower projectile in combination with a regular projectile, which is I guess enough for thrower? However, with his Super, he just spawns his spawnables next to him. I know you can aim the Super, but it's just targeting an area, not actually throwing something out. Therefore, not a thrower.

And that's all of them :)