Ok, let me see if I get it...
You want a deck that:
- Grows exponentially (or at least better than lineally)
- Gets even more exponential late game
- Heals yourself and buff creatures
All of that?
Huh, ideas fly all over, but growth higher than lineal, as I see it, are:
- Dune Scorps (needs buffing)
- Death effects+Growth (Schrod's cat+Vultures/Boneyard+Flooding+Vultures)
- Spamming lineally-growing creatures (spammers and growing creatures)
Dune scorps can be paired with:
Entropy, along with AM to heal, and some RT's to make it more fun.
Light, with Sanc to heal, and sundials, but this is too generic already.
Gravity, using both Acceleration and Momentum, and dunno what else but it's slightly more original...
Death effects+Growth, if you want to heal, have to be Entropy intensive, or at least, they can't run Entropy off-mark... Anyways, I don't know how to do a good deck with this archetype.
Spamming stuff can be done with spammer creatures (FFQ, Pharaoh) or growing creatures (Oty, Lava Golem, Fire Eater, Forest Spirit, Fire Spirit, Steam Machine), and you'll need to use Fractal/Mitosis on them. Anyways, you already pointed out that FFQ/Rustler/Emphatic bond/Mitosis?? deck; and I also see Mitosis/Oty/Bonds/Acceleration(for the final burst)/Grav Shield?? as a somehow good idea.
IDK if I helped you at all, mostly since this is something you may have already thought about, but I mainly want to see if this is what you meant in the OP...