I know, rather inefficient, but with red as good as it is in Magic and likely to be found across your Commander table, you can almost call Dwarven Pony a cheaper Rogue's Passage
7 Gix, Yawgmoth Praetor - Mythic Rare Extended Art - $18.51 Sitting at three mana Gix, Yawgmoth Praetor slots right into the current Standard mono-black decks
This also lets you run Shaymin for its Sky Support ability, since it can make Dialga ex retreat for less
9: Search your graveyard and library for any number of red instant and/or sorcery cards, exile them, then shuffle your library
Onix is a nice tech for decks with DCEs and Energy Acceleration to deal with Zoroarks
Shoutout to Perplexing Test, which acts as a one-sided mass bounce spell for token decks