Freaks? Wouldn't say so.
Bezerk? Their minimum gets in the way of that sometimes but can see where you're coming from.
FPC, La Junta and Uppers with their high damage cards.
Support clans - There are quite a lot that could fit this category, Uppers do have some very solid cards for Mono, but I also think that Junkz + Sents are more solid so are more often used in higher Elo too, also worth mentioning.
Power Mod clans, well Watu when they've got Moai available, but they still make killer half decks with Numar, Eugene, Dave + Mango, All stars without their banned cards are great as well, if you compare them directly to Watu they give them real competition if you think of Striker, Mulligan, Jessie + Cardigan to compare to. Bangers also do great, Kreenk Ld, Graff, Blaaster Cr if he ever gets un-banned but they have great 4* to like Vermyn N + Kurt now.
So top pick for me would probably be AS personally.
SoB clans, well that depends on bans quite a bit.
Dj Korps, Edwin, Pan, Artus, Oshitsune as well as Glorg and other cards tends to be the main NM cards being used,
Ursula, Ector, Langren, Hawkins, Bonnie Ld, Raeth, the list can go on for the list of useful Piranas.
Piranas though tend to have slightly lower damage and be less solid I think vs SoA, depending on the week I say more and more people are seeing the uses of Pirana now.
Granted, but they can make killer half decks.
Difference between Ector + Pan is small, difference between Ursula + Oshitsune greater but still similar cards, Piranas have more tactical cards I guess with Bonnie Ld + Hawkins. And Dj Korps NM have, Piranas got Langren which is kinda similar, or Fischer for same star count although I appreciate his will occur less often.