I'm sure that site contributor Erccre147 is a hero to all the tuba, trombone, and baritone players who love Friendship is Magic. The resources he shares for these instruments are always excellent.
So I'm happy to say that Erccre147 has shared some new sheet music with us here at Everypony Sings. He has written bass, trombone, and baritone resources for two songs: Smile, Smile, Smile (tuba version and trombone/baritone version) and the Gypsy Bard from Friendship is Witchcraft (tuba version and trombone/baritone version).
The last resource Erccre147 shared is slightly different. It's a brass arrangement of Discord (The Living Tombstone's Remix). The sheet music is written for four trumpet parts (though you'd actually need more than four trumpets to play it), trombone, euphonium, tuba, and percussion. It's a massive undertaking, so I'm very impressed by Erccre147's great work!