Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Frontier Mastodon

Ferocious — Frontier Mastodon enters the battlefield with a +1/+1 counter on it if you control a creature with power 4 or greater.

Ghired, Conclave Exile

When Ghired, Conclave Exile enters the battlefield, create a 4/4 green Rhino creature token with trample.
Whenever Ghired attacks, populate. The token enters the battlefield tapped and attacking. (To populate, create a token that's a copy of a creature token you control.)

Oreskos Explorer

When Oreskos Explorer enters the battlefield, search your library for up to X Plains cards, where X is the number of players who control more lands than you. Reveal those cards, put them into your hand, then shuffle.

Endless Sands

{T}: Add {C}.
{2}, {T}: Exile target creature you control.
{4}, {T}, Sacrifice Endless Sands: Return each creature card exiled with Endless Sands to the battlefield under its owner's control.

Sandsteppe Outcast

When Sandsteppe Outcast enters the battlefield, choose one —
• Put a +1/+1 counter on Sandsteppe Outcast.
• Create a 1/1 white Spirit creature token with flying.

Myriad Landscape

Myriad Landscape enters the battlefield tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.