Titan of Littjara

As Titan of Littjara enters the battlefield, choose a creature type.
Titan of Littjara is the chosen type in addition to its other types.
Whenever Titan of Littjara enters the battlefield or attacks, you may draw a card for each other creature you control that shares a creature type with it. If you do, discard a card.

Species Gorger

At the beginning of your upkeep, return a creature you control to its owner's hand.

Adaptive Automaton

As Adaptive Automaton enters the battlefield, choose a creature type.
Adaptive Automaton is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Willow Geist

Trample
Whenever one or more cards leave your graveyard, put a +1/+1 counter on Willow Geist.
When Willow Geist dies, you gain life equal to its power.

Frogify

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)

Galloping Lizrog

Trample
When Galloping Lizrog enters the battlefield, you may remove any number of +1/+1 counters from among creatures you control. If you do, put twice that many +1/+1 counters on Galloping Lizrog.

Plaxcaster Frogling

Graft 3 (This creature enters the battlefield with three +1/+1 counters on it. Whenever another creature enters the battlefield, you may move a +1/+1 counter from this creature onto it.)
{2}: Target creature with a +1/+1 counter on it gains shroud until end of turn. (It can't be the target of spells or abilities.)

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Papercraft Decoy

When Papercraft Decoy leaves the battlefield, you may pay {2}. If you do, draw a card.

Crocanura

Reach (This creature can block creatures with flying.)
Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Steeple Creeper

{3}{U}: Steeple Creeper gains flying until end of turn.

Whiptongue Frog

{U}: Whiptongue Frog gains flying until end of turn.

Halo Hopper

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.)

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters the battlefield, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Excavating Anurid

When Excavating Anurid enters the battlefield, you may sacrifice a land. If you do, draw a card.
Threshold — As long as seven or more cards are in your graveyard, Excavating Anurid gets +1/+1 and has vigilance.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Trollbred Guardian

{2}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.

Burrog Befuddler

Flash
When Burrog Befuddler enters the battlefield, target creature an opponent controls gets -1/-0 until end of turn.

Frogmite

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Grolnok, the Omnivore

Whenever a Frog you control attacks, mill three cards.
Whenever a permanent card is put into your graveyard from your library, exile it with a croak counter on it.
You may play lands and cast spells from among cards you own in exile with croak counters on them.

Froghemoth

Trample, haste
Whenever Froghemoth deals combat damage to a player, exile up to that many target cards from their graveyard. Put a +1/+1 counter on Froghemoth for each creature card exiled this way. You gain 1 life for each noncreature card exiled this way.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters the battlefield, choose a creature type.
Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

Haze Frog

Flash (You may cast this spell any time you could cast an instant.)
When Haze Frog enters the battlefield, prevent all combat damage that other creatures would deal this turn.

Jade Avenger

Bushido 2 (Whenever this creature blocks or becomes blocked, it gets +2/+2 until end of turn.)

Croaking Counterpart

Create a token that's a copy of target non-Frog creature, except it's a 1/1 green Frog.
Flashback {3}{G}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Chub Toad

Whenever Chub Toad blocks or becomes blocked, it gets +2/+2 until end of turn.

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Bloated Toad

Protection from blue
Cycling {2} ({2}, Discard this card: Draw a card.)

Leapfrog

Leapfrog has flying as long as you've cast an instant or sorcery spell this turn.