The Bulgarian team is mainly a way for us to meet internationally renowned Seeker Viktor Krum before he comes to Hogwarts. And we have to admit, he plays a very impressive match. Not only does he fly some cool maneuvers, but Viktor also manages to catch the Snitch even though he just broke his nose by getting a Quaffle straight to the face. As Hermione puts it, "He was very brave, wasn't he?" (8.144).
As for the other Bulgarian national team players, the Beaters Volkov and Vulchanov do their best to knock the Irish Chasers away from the Bulgarian side. Once of their Chasers, Ivanova, scores a goal. We're not quite as impressed with Keeper Zograf, who gets called with a foul, as does the second Chaser, Dimitrov. The third Chaser, Levski, barely seems to appear in the game at all, except to pass the Quaffle to other players. At any rate, the Bulgarian side puts up a good fight: as the Bulgarian Minister of Magic says, "Vell, ve fought bravely" (8.146).