At the beginning of your upkeep, if you control five or more lands, put four +1/+1 counters on Scute Mob.

Scuttling Doom Engine can't be blocked by creatures with power 2 or less.
When Scuttling Doom Engine dies, it deals 6 damage to target opponent or planeswalker.

Seaside Citadel enters the battlefield tapped.
: Add , , or .

(Seat of the Synod isn't a spell.)
: Add .

Secluded Steppe enters the battlefield tapped.
: Add .
Cycling (, Discard this card: Draw a card.)

: Add .
, : Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Landfall — Whenever a land enters the battlefield under your control, you may pay . If you do, draw a card.

Sejiri Refuge enters the battlefield tapped.
When Sejiri Refuge enters the battlefield, you gain 1 life.
: Add or .

Selesnya Sanctuary enters the battlefield tapped.
When Selesnya Sanctuary enters the battlefield, return a land you control to its owner's hand.
: Add .

Serra Avatar's power and toughness are each equal to your life total.
When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.

Flying
Whenever an artifact creature you control deals combat damage to a player, you may create a 1/1 blue Thopter artifact creature token with flying.

Whenever you cast an enchantment spell, create a 4/4 white Angel creature token with flying.

: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Flying
Whenever Silent Sentinel attacks, you may return target enchantment card from your graveyard to the battlefield.

Ninjutsu (, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Silent-Blade Oni deals combat damage to a player, look at that player's hand. You may cast a spell from among those cards without paying its mana cost.

Simic Growth Chamber enters the battlefield tapped.
When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.
: Add .

When you cast this spell, copy it for each time you've cast your commander from the command zone this game.
Each opponent sacrifices a creature. Each opponent who can't loses half their life, rounded up.

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals damage to an opponent, you may draw a card."
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

: Add .

, Sacrifice Soul Snare: Exile target creature that's attacking you or a planeswalker you control.