Other creatures you control get +1/+1 and have vigilance.
Spellcharge 5

When Remnant of Zakros enters, choose one —
• Each player sacrifices a creature.
• Each player sacrifices an enchantment.

When Renowned Roughrider enters or leaves the battlefield, create a 1/1 white Human creature token. Then if you control four or more creatures, put a +1/+1 counter on a creature you control.
Wander {4}{W}{W}

Replicated Regiment enters with a +1/+1 counter and a vigilance counter on it.
At the beginning of your upkeep, you may move a counter from Replicated Regiment onto another creature.

Reach
Replicrawler gets +1/+1 for each other artifact creature you control.
If you would create a token, you may pay {B}. If you do, create a token that's a copy of Replicrawler instead.

Drop — Reptilian Raver enters with two +1/+1 counters on it if you didn't cast any creature spells during your last turn.

When Research Grant enters, look at the top three cards of your library. Put one into your hand and the rest into your graveyard.
You've cast two or more spells this turn.
You've drawn two or more cards this turn.

At the beginning of combat on your turn, you may pay {1}. If you do, create a 1/1 red and green Elemental creature token. It gains haste. Sacrifice it at end of combat.

When Resourceful Hireling enters, choose one —
• Create a 0/0 colorless Robot artifact creature token with a +1/+1 counter on it.
• Create a Treasure token.

{T}: Add {C}.
Whenever Resting Place attacks, sacrifice it at end of combat.
Spellcharge 5

When Retrofit Paladin enters, tap up to two target creatures with power 3 or less.

Defender
As long as you control a creature with power 4 or greater, Revel Watchguard can attack as though it didn't have defender.

Flying
Drop — When Revenant Benefactor enters, if you didn't cast any creature spells during your last turn, return target creature card from your graveyard to the battlefield.

Once each turn, when a creature with power 2 or less you control enters, you may pay {1}. If you do, draw a card.
{1}{W}: Level 2
At the beginning of combat on your turn, put a +1/+1 counter on up to one target creature you control.
{3}{W}: Level 3
When this Class becomes level 3, exile target nonland permanent an opponent controls until this Class leaves the battlefield.

Revolutionary Redistributer enters with three +1/+1 counters on it.
At the beginning of combat on your turn, you may move a counter from a permanent you control to a second permanent you control.

When Revolutionary Supplier enters, you may search your library for a card named Explosive Canister and/or a card named Fencer's Foil, reveal them, put them into your hand, then shuffle.
The first artifact spell you cast each turn costs {1} less to cast.

Trample
Whenever Revolutionary Throng attacks, if you control another creature with power 4 or greater, it gets +2/+0 until end of turn.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast legendary spells or activate abilities of legendary permanents.
{3}, {T}, Sacrifice Revolutionary's Retreat: You may return target legendary card from your graveyard to your hand.

When Revved Robo enters, you may put a +1/+1 counter on it. If you don't, it gets +2/+0 and gains haste until end of turn.

When Rib Collector enters, if it wandered, return target creature card from your graveyard to your hand.
Wander—{1}{B}, Sacrifice another creature.

When Riotous Rockers enters, it deals 3 damage to up to one target that was dealt damage this turn.

Reach
When Roaming Treefolk enters, target creature or Ruin gets +2/+2 until end of turn.
Wander {5}{G}

Whenever Rogue Justiciar becomes the target of a spell or ability you control, you may tap target creature. This ability triggers only once each turn.

Whenever Rooftop Slink deals combat damage to a player, you may have each player discard a card.
Cybersoul {3}{B}

Flash
Flying