Equipped creature gets +2/+2 and has trample.
Whenever equipped creature deals combat damage to a player, choose a creature type. Create a Treasure token for each creature you control of that type.
Equip

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip

: Choose a color. Add one mana of that color unless any player pays . Activate only as an instant.

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

When Gwen Stacy enters, exile the top card of your library. You may play that card for as long as you control this creature.
: Transform Gwen Stacy. Activate only as a sorcery.

Return target nonland permanent you don't control to its owner's hand.
Overload (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander
Equip

: Add .

Equipped creature gets +2/+2 and has protection from white and from blue.
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Equip

Tarmogoyf's power is equal to the number of card types among cards in all graveyards and its toughness is equal to that number plus 1.

Flying
Whenever one or more creatures deal combat damage to you, each opponent sacrifices a creature of their choice that dealt combat damage to you this turn. The Ring tempts you.
Discard a card: Witch-king of Angmar gains indestructible until end of turn. Tap him.

: Add .
: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for rather than its mana cost.)
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.

: Add .
: Add or . This land deals 1 damage to you.

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Pay 3 life: Add .

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Search your library for a creature card, reveal it, then shuffle and put the card on top.

This land enters tapped unless you have two or more opponents.
: Add or .