Before this, salamangreat held the spot of "most competitive structure deck", but it cost slightly more than ninja to properly build out, so it ended up dropping off. Of course these days the best free-to-play decks are swordsoul and branded from their respective follower campaigns

I'll go ahead and say ninja. While it wasn't a top deck, ninja was good enough to at least be competitive in the meta. But more importantly, you could get it as a structure deck, making it by FAR the cheapest good deck you could get, boosting its play rate à la evilswarm in dragon ruler format

Liking and replying has me feeling like this