In Chapter 3, we have the Pleides Saints trying to rescue two of their members who have been captured by a witch and succeeding. Yeah, it gets worse later on, but for a moment The Power of Friendship actually worked with none of the girls dying, a nice change of pace from the dark nature of the series.
Mirai gets hers in Chapter 9, made even better because she was on the verge of going Out of Focus. It involves summoning an army of teddy-bears, riding on a giant bear, and cutting a witch in half.
And did we mention that the bears in question all have fangs, and that Mirai cut said witch in half by turning her cute little heart wand into a GIANT SWORD. She then cheerily asked Saki if she was alright with no concern to the fact that she was drenched in the witch's blood.
Kaoru in Chapter 19 uses Rosso Phantasma.
Niko managing to create her own Incubator through research and using her Soul Gem in Chapter 21's flashback. Sure it was ineffective in the end, but it was a pretty impressive feat.
Similarly, there's also Umika with the aid of the other Pleides Saints casting a memory spell over all of Asunaro City which barred the Incubators from being perceived by anyone thereby preventing them from making any more contracts and replacing all existing memories of Kyubey with Jyubey. While it did come to backfire on them, it was still a rather spectacular feat given that they were able to affect a whole city and keep it up. Even Kyubey admits to being impressed by the plan.
While we're at it, let's not forget that Kanna Hijiri managed to create a Witch that even Kyubey mistook for Walpurgisnacht for a moment. It too uses the forms of whatever Magical Girls happened to go into creating it as familiars, is just about as massive as the other Witch in question, and Kyubey even goes as far as naming the thing in respect of her; Hyades Daybreak. The rabbit-cat seemed to genuinely respect her for being able to do that, at least as much as he was capable of being.