Lorn, the Bereft3U
Legendary Creature — Spirit
Whenever a creature attacks, if you're the defending player, untap target creature you control.
Whenever a creature you control blocks, you may draw a card.
Partner (You can have two commanders if both have partner.)
1/5
Next: A non-blue commander who somehow manipulates steps or phases.
Officer Dormond1WU
Legendary Creature — Human Soldier
Whenever a creature you control becomes the target of a spell or ability an opponent controls, investigate. (Create a colorless Clue artifact token with "2, Sacrifice this artifact: Draw a card.) (W/U): Change the target of target spell or ability that targets a creature an opponent controls to target creature you control.
1/3
(I don't know how well this fulfills the requirement.)
Next: A Commander that makes me say, "Oooh! The flavor!"
Asaedron, Gentle GiantGWU
Legendary Creature — Giant
Trample
Asaedron, Gentle Giant deals damage to players in the form of cards drawn and to creatures in the form of +1/+1 counters.
Your opponents and permanents those players control have hexproof.
7/7
Schelos, CaromancerG
Legendary Creature — Elf Wizard GU, t: Put a +1/+1 counter on target creature. BG, t: Put target creature card in your graveyard on the bottom of your library. 2GUB: Remove all counters from all permanents. For each counter removed this way, each opponent loses 1 life and you draw a card.
Ojutai, the Great Teacher1URW
Legendary Creature — Elder Dragon
Flying
Whenever you cast a noncreature spell, you may pay WU. If you do, you draw a card and gain 2 life.
Whenever you cast a noncreature spell, you may pay UR. If you do, ~ deals 2 damage to each opponent and you draw a card.
4/4
Sulthet, the Warmind1R
Legendary Creature — Elemental Wizard
Haste 2W: Put a 1/1 white Soldier creature token onto the battlefield. 3U, t: Whenever a creature enters the battlefield this turn, you may draw a card.
1/3
NEXT: A commander from across the seas of Innistrad
Taraka, Charismatic Hero RWU
Legendary Creature — Human Knight
Vigilance
Whenever ~ becomes blocked by that creature, gain control of that creature. (That creature is removed from combat. This effect doesn't end at end of turn.) He has yet to meet someone he couldn't charm.
3/3
Next: A W commander with U, B,R, and G in its text box.
Katia, Shadow Caster3UB
Planeswalker — Katia
[+2] Each player draws a card, then each opponent discards a card.
[0] Put a -1/-1 counter on target creature. It gains "Whenever this becomes the target of a spell or ability, sacrifice it."
[-4] Put a token onto the battlefield that's a copy of target creature card in a graveyard or in a command zone, except it has "Whenever this becomes the target of a spell or ability, sacrifice it."
Katia, Shadow Caster can be your commander.
{3}
Next: A commander that encourages playing two different tribes.
Amesha Lasnara3W
Legendary Creature — Angel
Flying 1G, t: Reveal the top card of your library. If it's a land card or a creature card with converted mana cost 2 or less, put it into the battlefield. If not, you gain 2 life. 1U: Look at the top three cards of your library and put them back in any order.
0/4
Laora the Striker2RW
Legendary Creature — Goblin Warrior
First strike
Creature cards in your hand have dash. Their dash cost is equal to their mana cost minus 2.
Other creatures you control get +1/+1.
3/3
Tarshan, Carven Philosopher3
Legendary Artifact Creature — Golem
Defender 6GW: Search your library for up to two creature cards with defender and put them onto the battlefield, then shuffle your library. 6UB: Each player draws a card and loses 1 life for each creature you control with defender.
3/3
Vergelli, Worldly Nemesis 2WRB
Legendary Creature - Bird Wizard
Flying
Whenever a creature would enter the battlefield from anywhere other than an opponent's hand, put it onto the battlefield under your control instead. Sacrifice it at the next end step.
Whenever you gain control of a creature, you may tap or untap target permanent.
4/3
I just have to say that your current wording is quite broken. What it really wants to say is "Whenever a creature would enter the battlefield, if it wasn't cast [...]," because it's very rare that a creature enters the battlefield from a player's hand. They enter from the stack, mostly.
I would also argue that it wants to be blue, but I suppose that could be up for debate.
Every magic card with Invoker in its name has an ability that costs 8 mana to activate. I'm guess this is a reference to them?
Eldas, Eightfold Invoker4GGUU
Legendary Creature — Octopus Hydra (R)
Hexproof, trample 7G: Put eight +1/+1 counters on target creature. 7U: Draw a card for each +1/+1 couter on target creature. His power only grows with time.
8/8
Like the Planeswalker spells from the core sets — Chandra's Phoenix , Sorin's Thirst , Nissa's Expedition, but as a legendary creature and acting as a lieutenant perhaps... Sorry, that was super unclear. Let's retry.
NEXT: A friend or partner of a Commander precon commander.
Solunara, Flame of EternityRGW
Legendary Creature — Phoenix
Flying, vigilance
At the beginning of your upkeep, if Solunara, Flame of Eternity is in your command zone, you may choose a legendary creature card in your graveyard. If you do, put that card info you command zone and it becomes your commander in addition to your other commanders until it moves to your hand or library.
3/3
Next: A "signature spell" of a preexisting Commander from one of the Commander-series decks, or from one of the legends on this page
Baatar, First to Breathe4R
Legendary Creature — Dragon (M)
Flying W, T: Target permanent doesn't untap during its controller's next untap step. U, T: Draw a card. B, T: Target creature gets -1/-1 UEOT. G, T: Baatar, First to Breathe gets +2/+2 until end of turn. 1, Tap an untapped creature you control: Untap Baatar.
4/4
Legendary Creature — Spirit
Whenever a creature attacks, if you're the defending player, untap target creature you control.
Whenever a creature you control blocks, you may draw a card.
Partner (You can have two commanders if both have partner.)
1/5
Next: A non-blue commander who somehow manipulates steps or phases.
Legendary Creature — Human Soldier
Whenever a creature you control becomes the target of a spell or ability an opponent controls, investigate. (Create a colorless Clue artifact token with "2, Sacrifice this artifact: Draw a card.)
(W/U): Change the target of target spell or ability that targets a creature an opponent controls to target creature you control.
1/3
(I don't know how well this fulfills the requirement.)
Next: A Commander that makes me say, "Oooh! The flavor!"
Legendary Creature — Giant
Trample
Asaedron, Gentle Giant deals damage to players in the form of cards drawn and to creatures in the form of +1/+1 counters.
Your opponents and permanents those players control have hexproof.
7/7
Next: A commander that wants Mindlock Orb and/or Aven Mindcensor in its deck.
Legendary Creature — Elf Wizard
GU, t: Put a +1/+1 counter on target creature.
BG, t: Put target creature card in your graveyard on the bottom of your library.
2GUB: Remove all counters from all permanents. For each counter removed this way, each opponent loses 1 life and you draw a card.
Next: A commander that hoses certain strategies, like Anafenza, the Foremost or Gaddock Teeg.
Legendary Creature — Elder Dragon
Flying
Whenever you cast a noncreature spell, you may pay WU. If you do, you draw a card and gain 2 life.
Whenever you cast a noncreature spell, you may pay UR. If you do, ~ deals 2 damage to each opponent and you draw a card.
4/4
Next: A commander that is also equipment.
Legendary Creature — Elemental Wizard
Haste
2W: Put a 1/1 white Soldier creature token onto the battlefield.
3U, t: Whenever a creature enters the battlefield this turn, you may draw a card.
1/3
NEXT: A commander from across the seas of Innistrad
Legendary Creature — Human Knight
Vigilance
Whenever ~ becomes blocked by that creature, gain control of that creature. (That creature is removed from combat. This effect doesn't end at end of turn.)
He has yet to meet someone he couldn't charm.
3/3
Next: A W commander with U, B,R, and G in its text box.
Planeswalker — Katia
[+2] Each player draws a card, then each opponent discards a card.
[0] Put a -1/-1 counter on target creature. It gains "Whenever this becomes the target of a spell or ability, sacrifice it."
[-4] Put a token onto the battlefield that's a copy of target creature card in a graveyard or in a command zone, except it has "Whenever this becomes the target of a spell or ability, sacrifice it."
Katia, Shadow Caster can be your commander.
{3}
Next: A commander that encourages playing two different tribes.
Legendary Creature — Angel
Flying
1G, t: Reveal the top card of your library. If it's a land card or a creature card with converted mana cost 2 or less, put it into the battlefield. If not, you gain 2 life.
1U: Look at the top three cards of your library and put them back in any order.
0/4
Next: A white demon
Legendary Creature — Goblin Warrior
First strike
Creature cards in your hand have dash. Their dash cost is equal to their mana cost minus 2.
Other creatures you control get +1/+1.
3/3
Next: An Avatar of law
Legendary Artifact Creature — Golem
Defender
6GW: Search your library for up to two creature cards with defender and put them onto the battlefield, then shuffle your library.
6UB: Each player draws a card and loses 1 life for each creature you control with defender.
3/3
Next: Treefolk, Sphinx, or Demon tribal helper
I just have to say that your current wording is quite broken. What it really wants to say is "Whenever a creature would enter the battlefield, if it wasn't cast [...]," because it's very rare that a creature enters the battlefield from a player's hand. They enter from the stack, mostly.
I would also argue that it wants to be blue, but I suppose that could be up for debate.
Every magic card with Invoker in its name has an ability that costs 8 mana to activate. I'm guess this is a reference to them?
Eldas, Eightfold Invoker 4GGUU
Legendary Creature — Octopus Hydra (R)
Hexproof, trample
7G: Put eight +1/+1 counters on target creature.
7U: Draw a card for each +1/+1 couter on target creature.
His power only grows with time.
8/8
Next: Another dual-color invoker
NEXT: A friend or partner of a Commander precon commander.
Legendary Creature — Phoenix
Flying, vigilance
At the beginning of your upkeep, if Solunara, Flame of Eternity is in your command zone, you may choose a legendary creature card in your graveyard. If you do, put that card info you command zone and it becomes your commander in addition to your other commanders until it moves to your hand or library.
3/3
Next: A "signature spell" of a preexisting Commander from one of the Commander-series decks, or from one of the legends on this page
Legendary Creature — Dragon (M)
Flying
W, T: Target permanent doesn't untap during its controller's next untap step.
U, T: Draw a card.
B, T: Target creature gets -1/-1 UEOT.
G, T: Baatar, First to Breathe gets +2/+2 until end of turn.
1, Tap an untapped creature you control: Untap Baatar.
4/4
Next: A creature in a cycle with Baatar.