Trail of Mystery

Whenever a face-down creature enters the battlefield under your control, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle your library.
Whenever a permanent you control is turned face up, if it's a creature, it gets +2/+2 until end of turn.

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.

Whenever a face-down creature enters the battlefield under your control, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle your library.\r
Whenever a permanent you control is turned face up, if it's a creature, it gets +2/+2 until end of turn.

Duskmourn: House of Horror Commander

Murders at Karlov Manor Commander

Whenever a face-down creature enters the battlefield under your control, 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.