Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Gisela, Blade of Goldnight

Flying, first strike
If a source would deal damage to an opponent or a permanent an opponent controls, that source deals double that damage to that player or permanent instead.
If a source would deal damage to you or a permanent you control, prevent half that damage, rounded up.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Fiery Emancipation

If a source you control would deal damage to a permanent or player, it deals triple that damage to that permanent or player instead.

Predatory Focus

You may have creatures you control assign their combat damage this turn as though they weren't blocked.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Sweeping Cleave

Target creature you control gains double strike until end of turn. (Then exile this card. You may cast the artifact later from exile.)

Have

Two-Handed Axe

Whenever equipped creature attacks, double its power until end of turn.
Equip {1}{R}

Two-Handed Axe // Sweeping Cleave

Tana, the Bloodsower

Trample
Whenever Tana deals combat damage to a player, create that many 1/1 green Saproling creature tokens.
Partner (You can have two commanders if both have partner.)

Lovisa Coldeyes

Each creature that's a Barbarian, a Warrior, or a Berserker gets +2/+2 and has haste.

Getting

Luxior, Giada's Gift

Equipped creature gets +1/+1 for each counter on it.
Equipped permanent isn't a planeswalker and is a creature in addition to its other types. (Loyalty abilities can still be activated.)
Equip planeswalker {1}
Equip {3}

Sower of Discord

Flying
As this creature enters, choose two players.
Whenever damage is dealt to one of the chosen players, the other chosen player also loses that much life.

Obosh, the Preypiercer

Companion — Your starting deck contains only cards with odd mana values and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
If a source you control with an odd mana value would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Invigorate

If you control a Forest, rather than pay this spell's mana cost, you may have an opponent gain 3 life.
Target creature gets +4/+4 until end of turn.

Fungus Frolic

Create two 1/1 green Saproling creature tokens. (Then exile this card. You may cast the creature later from exile.)

Brightcap Badger

Each Fungus and Saproling you control has "{T}: Add {G}."
At the beginning of your end step, create a 1/1 green Saproling creature token.

Brightcap Badger // Fungus Frolic

Shared Roots

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Tifa Lockhart

Trample
Landfall — Whenever a land you control enters, double Tifa Lockhart's power until end of turn.

Hotfoot Gnome

Haste
{T}: Another target creature gains haste until end of turn.

Neyith of the Dire Hunt

Whenever one or more creatures you control fight or become blocked, draw a card.
At the beginning of combat on your turn, you may pay {2}{R/G}. If you do, double target creature's power until end of turn. That creature must be blocked this combat if able. ({R/G} can be paid with either {R} or {G}.)

Reyhan, Last of the Abzan

Reyhan enters with three +1/+1 counters on it.
Whenever a creature you control dies or is put into the command zone, if it had one or more +1/+1 counters on it, you may put that many +1/+1 counters on target creature.
Partner (You can have two commanders if both have partner.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Jeska, Thrice Reborn

Jeska enters with a loyalty counter on her for each time you've cast a commander from the command zone this game.
0: Choose target creature. Until your next turn, if that creature would deal combat damage to one of your opponents, it deals triple that damage to that player instead.
−X: Jeska deals X damage to each of up to three targets.
Jeska, Thrice Reborn can be your commander.
Partner

Mountain

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Aurelia, the Warleader

Flying, vigilance, haste
Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.

Gratuitous Violence

If a creature you control would deal damage to a permanent or player, it deals double that damage instead.

Forest

Bravado

Enchant creature
Enchanted creature gets +1/+1 for each other creature you control.

Lightning, Army of One

First strike, trample, lifelink
Stagger — Whenever Lightning deals combat damage to a player, until your next turn, if a source would deal damage to that player or a permanent that player controls, it deals double that damage instead.