Whenever another nontoken creature you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Oxen you control have double strike.
Whenever Bruse Tarl enters or attacks, exile the top card of your library. If it's a land card, create a 2/2 white Ox creature token. Otherwise, you may cast it until the end of your next turn.

Target creature gets +1/+1 until end of turn. Untap that creature.

Spree (Choose one or more additional costs.)
+ — Put two +1/+1 counters on target creature.
+ — Target creature gains trample until end of turn.
+ — Until end of turn, target creature gains "Whenever this creature deals combat damage to a player, draw two cards."

( can be paid with either or .)
: Target player draws a card. Activate only as a sorcery.
: Target player discards a card. Activate only as a sorcery.

When this artifact enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Search your library for up to two basic Forest cards. If you control a Nissa planeswalker, instead search your library for up to three land cards. Reveal those cards, put them into your hand, then shuffle.

Whenever this creature attacks, you may search your library for a basic land card that doesn't share a land type with a land you control, put that card onto the battlefield, then shuffle.
: Create a 1/1 green Insect creature token. Put X +1/+1 counters on it, where X is the number of basic land types among lands you control. Activate only as a sorcery.

Counter target spell.
Cycling (, Discard this card: Draw a card.)

Create X 1/1 white Soldier creature tokens. If X is 5 or more, destroy all other creatures.

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
: Add . Target opponent gains control of this creature. (Activate only as an instant.)

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. That land becomes a 0/0 green and blue Fractal creature that's still a land. Put a +1/+1 counter on it for each land you had enter the battlefield under your control this turn.

Flying
: Draw a card, then put a +1/+1 counter on this creature.

: This creature gets +1/+1 until end of turn. Activate only once each turn. ( can be paid with one mana from a snow source.)

This creature enters with three -1/-1 counters on it.
Remove a -1/-1 counter from this creature: Put a -1/-1 counter on another target creature.

: Add .
, , Sacrifice a Desert: Exile all graveyards.

Vigilance
, Sacrifice this creature: Exile target player's graveyard.

When you unlock this door, this Room deals 6 damage to target creature an opponent controls. You gain life equal to the excess damage dealt this way.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Flying
When this creature enters, scry 1. (Look at the top card of your library. You may put it on the bottom.)

As an additional cost to cast this spell, exile two creature cards from your graveyard.
Trample