You may have this enchantment enter as a copy of an enchantment you control, except it has "At the beginning of your upkeep, you may exile this enchantment. If you do, return it to the battlefield under its owner's control."

Choose two —
• Counter target black-bordered spell.
• Return target creature to its owner's hand.
• Untap each permanent you control with a watermark.
• Roll two six-sided dice. Target player mills X cards, where X is the total of those results.

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Ishai.
Partner (You can have two commanders if both have partner.)

Target player sacrifices a creature of their choice.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Choose one —
• Counter target red spell.
• Destroy target red permanent.

At the beginning of your upkeep, each player draws a card.
Whenever an opponent draws a card, that player loses 1 life.

Sneak
Double strike
During your turn, you may cast creature spells with power or toughness 1 or less from your graveyard. If you cast a spell this way, that creature enters with a finality counter on it. (If a creature with a finality counter on it would die, exile it instead.)

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

Target creature you control deals damage equal to its power to another target creature. If excess damage was dealt this way, discover X, where X is that excess damage. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Put onto the battlefield under your control all creature cards in all graveyards that were put there from the battlefield this turn.

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Double strike
Other creatures you control get +1/+0 for each Aura and Equipment attached to Kellan.

: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on this enchantment.
At the beginning of your upkeep, if this enchantment has twenty or more growth counters on it, you win the game.

All Sliver creatures get +2/+0.

, Sacrifice this artifact: Exile target player's graveyard.

Haste
Whenever Captain Lannery Storm attacks, create a Treasure token. (It's an artifact with ", Sacrifice this token: Add one mana of any color.")
Whenever you sacrifice a Treasure, Captain Lannery Storm gets +1/+0 until end of turn.

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
: Add , , or .

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

Myriad
The "legend rule" doesn't apply to creature tokens you control.
Triggered abilities you control can't cause you to sacrifice or exile creature tokens you control.

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.