As a fan of action movies, I can recommend this ones
Just like you're looking for - tournament of an assasins, really like this movie
A Tournament too, but not only an assasins, a gangsters there too. Awesome film, looks silly sometimes, but it's awesome, idk how to say more
And this one maybe not 100% about tournament, more about a hunting season. But IMHO, it can qualify. Great action film, classic