Brutal Synergy!

To begin with this devastating combo, you'll need to have both Sunny Smiles, Iconic Friend (up to 3 is possible!) as well as Minuette, Clocked Up (again up to 3), out in play, preferably at your opponent's problem, and preferably with Bonus Points of 3.

Then play (face-down) a troublemaker, Nightmare Moon.
The following round, Nightmare Moon is revealed (turned face-up) and then the devastation begins!

First, all players discard their hands and draw 3 cards.
(In a multiplayer game this effect is even more devastating), but Sunny Smiles, Iconic Friend powers up +1 per card an opponent discards.
It's difficult to guess at how many cards your opponent(s) will have in their hand because the set up (getting 1-3 Sunny Smiles and 1-3 Minutettes out into play won't be early on in the game, not to mention what may happen in a multiplayer game). But for the sake of keeping things simple let's assume your opponent discards 4 cards. (But let's not forget or write off the possibility of your opponent having their maximum of 8 cards in their hand = +8! It is entirely possible for Sunny Smiles to power up to 11-power!)

Sunny Smiles, Iconic Friend powers up to +4 (giving her a total power for the remainder of the turn of 7). If this isn't enough to defeat the Problem, you can trigger another troublemaker phase by retiring a Minuette, Clocked Up, forcing your opponent to discard another card, powering up Sunny Smiles another +1.

You are still in your Troublemaker Phase. Immediately confront Nightmare Moon, defeat her and gain +3 points.
Then play through the Main Phase (building up Friends if needed - don't forget Sunny Smiles is still at 8 power!).

Then confront your opponent's problem, score 1 point (if you're the first, score it's bonus points (if planned right another 3), and then possibly, a Problem Faceoff - don't forget, Sunny Smiles is still at 8-power - (hopefully) win Problem Faceoff, score another 3 points.

If timed right and played right, this combo could score - if 1 turn - from 4 to 10 points! (That's approximately 25% - 67% of the game).

...ouch!...

Now, the downside of this strategy is you would need, probably 3 Nightmare Moons in your deck to make this functional.... and even 1 Nightmare Moon can be difficult to find (being Ultra-rare) or extremely expensive. :(