There was talk in the forums about coming up with more elements as well, the most popuar one being a machine-type element (I personally thought the counter to it could be a spirit-type element).
That does sound like a nice idea. There may be some problems contrasting Spirit with Aether, though.
These starter cards could be a very nice addition to tjhe game, although there sure are a heckuva lot of effects in there. IE: the dragons don't have any abilities 'cept the aether one.
Both of these decks would be very ability dependant. You may have noticed that none of the Parasite creatures are terribly powerful save the dragon (and even that is brought down 1/1 from a normal dragon to make up for it's ability). The Symbiote creatures, on the other hand, are all supposed to pair up and compliment each other. It would have to be balanced properly, but I don't think it's a problem.
piallrs get no abilities either
I called them "pillar" cards because they stick around, and all the cards like them have a pillar symbol on them (Nightfall, etc). I've changed it to pa"Permanent" to avoid confusion.
but i think many of the effects are completely overpowered/underpowered
Yeah, I tried to present them as balanced as possible, but without testing and careful analysis that's hard.
the bond is unfair, as it would be double the healing of life's version, which is almost 70% bent on healing
I'm not sure what you mean here. The Parasitic Bond doesn't heal, it just avoids damage (30%) similar to Dusk Mantle and Fog Shield, but it also redirects it to the enemy (thus the lower %
and higher cost). Also, it's entirely dependant on the enemy attack. Sure, if you're facing a ton of powerful creatures it's powerful, but against one photon it's useless.
and grasper should be changed to arm, and have 10/1 (?) with shell staying the same, and both having a passive ability of combine, when they are both on the field they both die (but don't trigger graveyard or bonewall) and create _____ with 10/10 (15/15?)
I though about that, but them fusing into one creature would be a little complicated, and I'm not sure I like the idea as a whole. Also, I thought about calling it "arm" or "claw", but "Grasper" sounded much more like an actual creature, and that's what these are supposed to be. Maybe change "Shell" to "Shelled XXX" to fit?
also a bunch of the cards from parasite cards could easily be death or darkness, and some of them seem to be death (infest), but most of the cards are very good 
Death and Darkness both have some of these features (Death gets poison, though non-scaling, and Darkness get's a Parasite and the parasitic Devourer) but none significantly and the concept doesn't seem to have been explored through the cards that exist.
...look, Elements are Elements. Building blocks of the World, found in places or such. There is Air and gasses, Water and liquids, Earth and solids, Fire, and so on. So, where is Parasite in this? What does Parasite build, its form in the world?
...seriously, if you're trying to make an element, try to find something in the World that is overlooked by the existing 12. I recommend going outside for that.
If you're talking the classic elements, there's Fire, Air, Earth, and Water, and nothing else. No light, no darkness, no time, no gravity, no entropy, no aether, no nothing. If you're talking chemical, we're all way off. Even if you go classical in other cultures, you still don't get more than 5 (Fire, Water, Air, Metal, and Wood in Japan). Face it, we're making up elements as we go, and Parasite and Symbiote is no more esoteric than Entropy, and definitely more than Aether (something that doesn't actually exist).
Overall i think there were a lot of nice ideas in there and nothing jumps off the page at me as highly overpowered right off the bat. For the most part those were pretty unique ideas too so props for that.
Thank you.
A number of them are quite powerful, but I tried to pair those with high costs or significant weaknesses.
