Plains

Timberland Ancient

Reach, trample
Forestcycling {2} ({2}, Discard this card: Search your library for a Forest card, reveal it, put it into your hand, then shuffle.)

Stoneskin

Flash
Enchant creature
Enchanted creature gets +0/+10.

Murder

Doran, the Siege Tower

Each creature assigns combat damage equal to its toughness rather than its power.

Skeleton Key

Equipped creature has skulk. (It can't be blocked by creatures with greater power.)
Whenever equipped creature deals combat damage to a player, you may draw a card. If you do, discard a card.
Equip {2}

Treefolk Umbra

Enchant creature
Enchanted creature gets +0/+2 and assigns combat damage equal to its toughness rather than its power.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Swamp

Bosk Banneret

Treefolk spells and Shaman spells you cast cost {1} less to cast.

Gnarled Grovestrider

Vigilance
Other creatures you control have vigilance.

Dormant Grove

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if that creature has toughness 6 or greater, transform Dormant Grove.

Dormant Grove // Gnarled Grovestrider

Forest

Orchard Warden

Whenever another Treefolk creature you control enters, you may gain life equal to that creature's toughness.

Rootless Yew

When Rootless Yew dies, search your library for a creature card with power or toughness 6 or greater, reveal it, put it into your hand, then shuffle.