Must Keep

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Titanic Growth

Target creature gets +4/+4 until end of turn.

Loot, Exuberant Explorer

You may play an additional land on each of your turns.
{4}{G}{G}, {T}: Look at the top six cards of your library. You may reveal a creature card with mana value less than or equal to the number of lands you control from among them and put it onto the battlefield. Put the rest on the bottom in a random order.

Colossification

Enchant creature
When Colossification enters, tap enchanted creature.
Enchanted creature gets +20/+20.