Mauso doesn't block buffs unfortunately (he does however block debuffs, if that's what you meant).
Harvest Jack does block buffs, however. Suzerain is another UH lego that's great for 21 because of the A3.
My leggos are Rotos and UDK at 60 and Skartorsis unbuilt. I'm using FB, Vogoth, Seeker, Husk, UDK, and Rotos. Rotos, UDK and Husk are on regardless, I've been rotating the others trying to pick a winning team, all to no avail.