My thoughts. There are no eldrazi cards here because I hate them.
Tier 1 (Definitely buy, almost certainly have a spot)
Oath of Jace: While it has less raw power then Compulsive Research and less synergistic explosiveness then atunement, Oath of Jace is a good compromise between the two.
Kalitas, Traitor of Ghet: A decent lifelink creature in black is definitely something I was looking for. I might eventually go to a custom card, but I'll try this dude for now.
Oath of Nissa: A green cantrip with enchantress/devotion implications is pretty cool.
Ayli, Eternal Pilgrin: I ran a custom enchantment very similar to this card and liked it, but it was too narrow. Putting it on a decent body, even if the activated abilities are slightly weaker, is probably the right direction.
Mira and Denn, Wildborn: Having exploration effects on cards with wildly different stats will help this theme cross over better.
Stormchaser Mage: Like Alphez, I'd consider running almost any prowess creature under 3 mana. I'm slightly skeptial of this design, but keyword salad creatures tend to be more fun then they look. Unless they say vigilance.
Hissing Quagmire: Its a dual land that doesn't suck.
Neddle Spires: Its a dual land that doesn't suck.
Wandering Fumerole: Its a dual land that doesn't suck.
Tier 2 (Almost certainly buy, will probably get played at least temporarily)
Chandra, Flamecaller: Seems pretty right. I like it better then Wildfire. Having 3 distinct and powerful modes is pretty crazy. Not sure of its niche, exactly, but probably works in the same places Crater Hellion does.
Oath of Chandra: Shitty removal spell, but plays with some nice themes.
Nissa, Voice of Zendikar: Possible Curse of Predation replacement. Endless chumping on a 3 mana planeswalker could be annoying.
Pulse of Murasa: I've been on the lookout for green incidental lifegain. The card seems sweet, but 6 life might be too much of a beating on certain decks.
Cliffhaven Vampire: Underpowered, but his heart is in the right place. Could be custom buffed.
Captain's Claws: Pretty cool equipment, an equipment that replaces its holder might be annoying.
Sea Gate Wreckage: ULD stuff, awesome for some harder to draft decks like red/black control that can easily get into topdeck wars.
Mirrorpool: ULD stuff, no clue who wants it.
Tier 3 (Probably buy, have the potential to see play)
Linvala, the Preserver: People keep saying Elspeth 6 is over the top, but I like her better then all the alternatives. Maybe Linvala is a replacement?
Vampire Envoy: Underpowered, but her heart is in the right place. Could be custom buffed. Probably some mashup between her and Cliffhaven. Likely Cliffhaven's ability on her body.
Embodiment of Fury: Pretty cool red 4 drop, but yeah, red 4 drop.
Goblin Dark Dwellers: Good, but I'm not sure I want this?
Oath of Gideon: Good synergies, but I'm not sure this is the effect I want.
Sylvan Advocate: Seems overpushed even if he hits the right design notes.
Corpse Churn: Not sure if this is how black should get cards, but black doesn't have much of way of filling the graveyard an it and probably should so maybe its cool.