As long as equipped creature is attacking, it has first strike and must be blocked if able.
Equipped creature has "If a creature dying causes a triggered ability of this creature or an emblem you own to trigger, that ability triggers an additional time."
Equip

: Add .
Channel — , Discard this card: It deals 4 damage to target attacking or blocking creature. This ability costs less to activate for each legendary creature you control.

This land enters tapped unless you control a Mountain or a Plains.
: Add or .

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Attacking creatures you control have double strike.

Change the text of target spell or permanent by replacing all instances of one color word with another.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever a creature deals damage to you, destroy it.
When Dread is put into a graveyard from anywhere, shuffle it into its owner's library.

Reach, trample
Whenever another creature you control enters, put X +1/+1 counters on it, where X is its power.
Plot (You may pay and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

When Sauron enters, gain control of target creature an opponent controls until end of turn. Untap it. It gains haste until end of turn.
: Creatures you control get +2/+0 until end of turn. Each opponent loses 2 life.

Rivendell enters tapped unless you control a legendary creature.
: Add .
, : Scry 2. Activate only if you control a legendary creature.

Whenever you cast a spell that targets only a single artifact or creature you control, create a token that's a copy of that artifact or creature, except it's not legendary.

Other black creatures you control get +1/+1.
Other green creatures you control get +1/+1.
At the beginning of your upkeep, you may create a 1/1 black and green Worm creature token.

When this creature dies, search your library for any number of creature cards with total mana value 6 or less, put them onto the battlefield, then shuffle.

Equipped creature gets +2/+0 and has deathtouch.
: Until end of turn, this Equipment gains "Whenever equipped creature deals combat damage to a player, that player loses the game."
Equip

As this land enters, you may reveal a Goblin card from your hand. If you don't, this land enters tapped.
: Add or .

At the beginning of each end step, each player discards their hand.

This spell costs less to cast for each instant and sorcery spell you've cast this turn.
Whenever this creature attacks, exile up to one target instant or sorcery card from your graveyard. Copy it. You may cast the copy.
You may cast this card from your graveyard by exiling four instant and/or sorcery cards from your graveyard in addition to paying its other costs.

Flying, trample
When RMS Titanic deals combat damage to a player, sacrifice it and create that many Treasure tokens.
Crew 3 (Tap any number of creatures you control with total power 3 or more: This Vehicle becomes an artifact creature until end of turn.)