Flying, vigilance, deathtouch, lifelink

At the beginning of your end step, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Bestow {2}{W}{U}{B}{R}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)

Flying, first strike, vigilance, trample, lifelink

Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink.

{T}: Add one mana of any color in your commander's color identity.

Whenever Dune-Brood Nephilim deals combat damage to a player, create a 1/1 colorless Sand creature token for each land you control.

Vigilance

Faeburrow Elder gets +1/+1 for each color among permanents you control.

{T}: For each color among permanents you control, add one mana of that color.

Whenever Glint-Eye Nephilim deals combat damage to a player, draw that many cards.

{1}, Discard a card: Glint-Eye Nephilim gets +1/+1 until end of turn.

Whenever a player casts an instant or sorcery spell, if that spell targets only Ink-Treader Nephilim, copy the spell for each other creature that spell could target. Each copy targets a different one of those creatures.

Destroy each creature that isn't all colors.

+1: Create a 3/3 Kavu creature token with trample that's all colors.

-3: Choose up to two target creatures. For each of them, put a number of +1/+1 counters on it equal to the number of colors it is.

-6: Return target multicolored card from your graveyard to your hand. If that card was all colors, draw a card and create two Treasure tokens.

Jared Carthalion can be your commander.

Flying

Whenever Maelstrom Archangel deals combat damage to a player, you may cast a spell from your hand without paying its mana cost.

Converge -- You draw X cards and you lose X life, where X is the number of colors of mana spent to cast this spell.

If Primeval Spawn would enter the battlefield and it wasn't cast or no mana was spent to cast it, exile it instead.

Vigilance, trample, lifelink

When Primeval Spawn leaves the battlefield, exile the top ten cards of your library. You may cast any number of spells with total mana value 10 or less from among them without paying their mana costs.

Flying

Other multicolored creatures you control get +1/+0.

Whenever another multicolored creature you control dies, return it to its owner's hand at the beginning of the next end step.

Vigilance, haste

As Saskia the Unyielding enters the battlefield, choose a player.

Whenever a creature you control deals combat damage to a player, it deals that much damage to the chosen player.

Flying, menace, haste

Whenever Two-Headed Hellkite attacks, draw two cards.

Whenever you cast a spell, you may put two +1/+1 counters on Witch-Maw Nephilim.

Whenever Witch-Maw Nephilim attacks, it gains trample until end of turn if its power is 10 or greater.

Whenever Yore-Tiller Nephilim attacks, return target creature card from your graveyard to the battlefield tapped and attacking.