Replenishing Blade 6
Artifact - U
Whenever a player puts a card from their library into their graveyard, you gain 1 life.
T: If you both own and control Replenishing Blade and a permanent called Depletion Shield, exile them and meld them into A Mech, Ra
A Mech, Ra (C)
Artifact Creature - U
Whenever A Mech, Ra, deals combat damage to an opponent, that opponent puts the top half of their library into their graveyard.
Whenever you or a permanent you control takes damage from a source you don't control, that source's controller puts that many cards from the top of their library into the graveyard.
Probably almost as cool as the god.

Blessing of the Warrior 2R
Enchantment - Aura C
Enchant Player
Creatures enchanted player controls get +1/+0.
Whenever you both own and control Blessing of the Warrior and a permanent called Curse of the Martyr, exile them both, then meld them into Honour of the Paladin.
Honour of the Paladin (WR)
Enchantment C
Creatures you control get +1/+1 and have lifelink.
The time for bleeding is over. We shall be healed, and you shall be the ones who bleed.

Hell's Hammer 7
Artifact - Equipment MR
Equip - Sacrifice 7 permanents
Equipped creature has Annihilator 7.
T: If Hell's Hammer is equipped to a creature called Stained Glass Demon and you own and control both permanents, exile them both, then meld them into Shattered Plans.
Shattered Plans (C)
Enchantment MR
At the start of each player's upkeep, return each permanent card from exile to the battlefield under your control, and each non-permanent card you own to your hand.
Sometimes, you just gotta start over.

Knight of Restoration 3WW
Creature - Human Soldier R
You can't sacrifice lands.
T: If you both own and control Knight of Restoration and a permanent called Lavaflow Dragon, exile them and meld them into Dragonlord Draconium
Dragonlord Draconium (WR)
Creature - Human Dragon Knight R
At the beginning of your upkeep, each opponent sacrifices a land.

Burning Bargain 1R
Enchantment R
When Burning Bargain enters the battlefield, it deals 2 damage to each creature your opponents control and each opponent.
At the beginning of your upkeep, you lose 2 life. Then, if you both own and control Burning Bargain and a permanent called Fel Bargain, exile them and meld them into Blank Slate.
Blank Slate (C)
Artifact R
T: Exile Blank Slate, then return it to the battlefield under your control (It returns as its constituent cards)
See, that wasn't so bad! Now, let's write up another deal...

Cobalt Spectre U
Creature - Spirit U
T: If you both own and control Cobalt Spectre and a permanent called Azure Soul, exile them, then meld them into Blue Ghost.
Blue Ghost (W/U)
Creature - Spirit Wizard U
Creatures you control have protection from black.
T: Untap each creature you control that isn't called "Blue Ghost".

City of Return
Legendary Land - City MR
(T: Add P to your mana pool)
T: If you both own and control City of Return and a permanent called Wasted Purple Land, exile them both and meld them into Portal of the Wastes
Portal of the Wastes
Legendary Land MR
T: Add PP to your mana pool.
C: Add P to your mana pool.
P: Add C to your mana pool.

(Done up to post 137)

If you're wondering why I haven't made a meld for your card, it could be that your card isn't complete (for example, it's a creature without P/T or without a cost), that it forces me to break rules (If your card is a legendary common, then it pretty much forces me to make a legendary common too), or that I just couldn't think of anything good to add.