Ancient Grudge is good in the sideboard

Good to see another Woooolves Deck, (sorry!)

Feel free to check mine out and compare...

Belgarath + Poledra

I think you could use some Moonmist. Immerwolf will help you keep your Werewolves flipped, but it won't flip them in the first place, and right now you have a (mostly) aggro gameplan, so you need a couple of ways to force your big boys to flip so that you can attack with them. It's also a nice combat trick as a bonus.

I've tested the deck with Moonmist, and honestly it ended up being dead much more often than it was helpful. As a flipping method, its more reliable to lock someone down with Magus of the Moon and flip when their GW shocklands or whatever tap for red than it is to hope I get Moonmist when its useful.

That's disheartening, because it dooms the deck to being slow. The aggro mirror (especially for decks like Affinity and Merfolk, who don't really care about Blood Moon) will be a struggle if that's the case.

Thats where sideboarding comes in for the most part. Taking out Moonmist actually speeds up the deck by allowing me to run more creatures, giving Collected Company more targets to hit. Running Moonmist would actually slow me down at this point

I would consider it a worthy sideboard combat trick in case you lose an aggro race on Game 1, though. You'll probably get more value from it than from a Domri Rade against Merfolk, for example.

Well I also have no clue what I'll be facing. It could be a good sideboard card against some decks, but for example I'm not gonna sideboard for Jund if nobody actually plays it against me (Yay $100 Liliana and $160 Goyf screwing up the format :D)