msem-instigator

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Leotau Rider encourages a creature, that creature gains trample until end of turn.

Trample
Lotusleaf Blade gets +1/+1 as long as you control another Warrior.

Pressure {G} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Deathtouch

Whenever another creature you control enters, you may pay {2}. If you do, judge that creature. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

Art of war — At the beginning of your end step, if Masamori Ranger dealt damage to an opponent this turn, search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

When Master of the Glen enters, create a 2/2 green Wolf Elemental creature token.
Elementals you control have trample.

Flash
Wanderlust — When Microzoologist enters, search your library for a creature card with mana value 1. If you control four or more differently named lands, you may search for a creature card with mana value 3 or less instead. Reveal that card, put it into your hand, then shuffle.

Mossvine Lurker has trample as long as it has a +1/+1 counter on it.

When Neo-Soul Naturalist enters, exile up to one target artifact or enchantment. Its controller conjures a card named Data-Point into their hand. (It's a sorcery that costs {2} with “Draw a card.”)

Vigilance (Attacking doesn't cause this creature to tap.)
Sacrifice a Fungus, Saproling, Plant, or Insect: Put a +1/+1 counter on Ontarachie Forager.

Whenever you cast a spell from exile, Promised Seeker gets +3/+3 until end of turn.
Prophecy {G} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

Trample
Art of war — At the beginning of your end step, if Raiun Bay Admiral dealt damage to an opponent this turn, put a +1/+1 counter on each other creature you control.

When Reconnaissance Expert enters, mill four cards.
When Reconnaissance Expert dies, return target noncreature permanent card from your graveyard to your hand.

Royster Hounds can't be blocked by creatures with power 2 or less.

Ruins Pack gets +2/+2 as long as you sacrificed a permanent this turn.

When Scuripi Collector enters, return target artifact, enchantment, or land card from your graveyard to your hand.

Flash
If one or more counters would be put on a creature you control, put that many plus one of each of those kinds of counters on that creature instead.

Whenever Silt Lurker deals combat damage to a player, mill three cards, then draw a card if seven or more cards are in your graveyard.
Cycling {G} ({G}, Discard this card: Draw a card.)

Silver-Dawn Elder gets +2/+2 as long as you control five or more lands.
Revive—{2}{G}{G}, Discard a card. ({2}{G}{G}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Another target creature you control gets +1/+1 until end of turn.
[Lore III] Search your library for a basic land card, put it onto the battlefield, then shuffle.

When Steelcharm Obliterator enters, choose one —
• Put two +1/+1 counters on Steelcharm Obliterator.
• Target creature you control fights another target creature.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever Steelhoof Battlechief attacks, another target attacking creature you control gets +2/+2 and gains trample until end of turn.

Improve {G} ({G}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever an Elf you control dies, you may search your library for a land card, reveal it, put it into your hand, then shuffle.

Vigilance
When Territorial Camaar enters, you may sacrifice a land. If you do, search your library for a Desert card, put it onto the battlefield tapped, then shuffle.