Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Simic Signet

Other Snake creatures you control get +2/+2.
Whenever a Snake you control deals combat damage to a player, you may draw a card.

({T}: Add {G}, {U}, or {R}.)
Ketria Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Permanents you control gain hexproof and indestructible until end of turn.

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

{T}: Add one mana of any color that a land an opponent controls could produce.

Frontier Bivouac enters tapped.
{T}: Add {G}, {U}, or {R}.

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

({T}: Add {R} or {G}.)
Cinder Glade enters tapped unless you control two or more basic lands.

If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.