Nishii, Vagrant Explorer

Whenever a creature you control attacks, it
explores.(Reveal the top card of your library. Put
that card into your hand if it's a land. Otherwise, put
a +1/+1 counter on this creature, then put the card
back or put it into your graveyard.)
If you reveal five or more different land cards
during your combat phase, untap all creatures
you control. After this combat phase, there is
an additional combat phase.