Master Juggler
At 6th level, you have become so accomplished at juggling and manipulating objects that you can put your skills to use in combat in two ways.
First, if you have multiple light, thrown weapons, you may juggle them during combat. If you take the Attack action while juggling, you can attack twice, instead of once. You must have both hands free to juggle. You may safely juggle a number of weapons equal to your Proficiency bonus during combat.
I think right here is the best ability made for a potential Jester sub-class. The thrown-weapon combat style is underplayed in the game right now, but letting someone get one additional attack with light / finesse / thrown weapons does not break the damage bank, and gives things like darts a foothold back in the game that they are currently missing. A Bard getting to throw three d4 damage darts per round (using TWF) would give those weapons back some heft. (The only potential concern would be the handaxe, as its the only light / finesse thrown weapon that is 1d6 rather than 1d4 and thus damage-wise might be a little too high with three attacks at level 1.)