When Lander enters, create X lander tokens (They re artifacts with "2, T, Sacrifice this token: Search you library for a basic land card, put it onto the battlefield tapped, then shuffle.)

Landerfall — Whenever a lander you control enters, put a +1/+1 counter on Lander.

2, T, Sacrifice Lander: Search you library for a basic land card, put it onto the battlefield tapped, then shuffle.