Dawntreader Elk

{G}, Sacrifice Dawntreader Elk: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Thunderblust

Haste
Thunderblust has trample as long as it has a -1/-1 counter on it.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Swamp

Springbloom Druid

When this creature enters, you may sacrifice a land. If you do, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.