Birthing Ritual

At the beginning of your end step, if you control a creature, look at the top seven cards of your library. Then you may sacrifice a creature. If you do, you may put a creature card with mana value X or less from among those cards onto the battlefield, where X is 1 plus the sacrificed creature's mana value. Put the rest on the bottom of your library in a random order.

Forest

Arboreal Grazer

Reach
When Arboreal Grazer enters, you may put a land card from your hand onto the battlefield tapped.

Risen Reef

Whenever Risen Reef or another Elemental you control enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Cankerbloom

{1}, Sacrifice Cankerbloom: Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Faerie Seer

Flying
When Faerie Seer enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Rubblebelt Maverick

When Rubblebelt Maverick enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
{G}, Exile Rubblebelt Maverick from your graveyard: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Elvish Pioneer

When Elvish Pioneer enters, you may put a basic land card from your hand onto the battlefield tapped.