
Whenever a face-down creature you control enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Whenever a permanent you control is turned face up, if it's a creature, it gets +2/+2 until end of turn.
Trail of Mystery has 5 printings, first in Khans of Tarkir (2014). EDHREC ranks it #6,220 among Commander cards. It appears most in Zimone, Mystery Unraveler decks (10,127 on EDHREC). 3 public decks on TCG run it.
Deck counts from EDHREC.
Cards that show up in the same decks on EDHREC.