A budget heartless summoning deck i came up with just now.
Combos and purposes:all of the combos are powered by Heartless Summoning (obviously)
Priest of Urabrask+ Brimstone VolleyFor a net cost of R, you can cast brimstone volley with morbid. heartless summoning turns priest of urabrask into essentially a red Dark Ritual as it will die when it hits the field. This will trigger morbid and you can use the three mana produced to cast the brimstone
Myr Superion and Perilous MyrWith heartless on the field, these guys both become free. You can have a free shock from perilous and a free beatstick from superion. Nice, but almost certainly dependent on heartless
Rage Thrower + Kuldotha Rebirth + Galvanic Juggernaut OR Myr SuperionAt 6 CMC a ragethrower would normally be way too heavy. At 4, he becomes very reasonable. With the thrower in play, cast kuldotha rebirth, saccing a juggernaut or superion. This will cause thrower's ability to trigger 4 times for a total of 8 damage. This basically turns rebirth into an awesome player - only goblin grenade.
Thopter Assembly + Rage ThrowerPlaying Thopter Assembly with Rage Thrower and heartless summoning in play triggers rage thrower 5 times. every turn!
Faithless LootingThis thing allows you to draw 2 and discard 2 for R. While it is destined to be a Flashback "god card", it can help you to tailor your hand to any situation (good if you have excess land for example). It can also help you to find a heartless summoning if you didn't get one in your opening hand (or if the one you did play got destroyed). It flashbacks for 2R, which is very nice.
Priest of UrabraskThis guy serves a dual purpose. In an emergency, he can be used to bring out a myr superion (if the heartless hasn't come up yet)
Bloodgift Demon more black and a solid draw engine. Also a good aerial beatstick (he plays as a 4/3 flier for 1BB with summoning out!)
Galvanic Juggernautbecause I can. And wurmcoil is too expensive in terms of cash cost.
