I still don't see how these are so different from Permanents to need a new card category.
In a way, they are like permanents but they are not.
* Can't be destroyed. Like a whip you can use without fear.
* Has a risk to bloat your hand (ie. bad with fractal)
* Very high activation cost. So you can't really spam it early / midgame.
These spells would be an option, not meant to be replacement of permanents (a very high cost spell vs low activation cost -or passive- permanent). Ie. a high cost- buyback spell version of feral bond would not be as attractive. Feral bond (or graveyard etc) is much more meaningful as a stacking permanent. But, lets say, deflagration has more of a "spell" ambiance. And when it comes to that, several spells & permanents already share the same effect only differing by their costs (Pulverizer vs Deflagration, Shockwave vs Owl's Eye, all nymphs). Following similarity=useless logic, I could argue nymphs are not needed in the game as they have spell counterparts. Permanents draw power of some spell goodies as of now, spells could do the same. A nymph is a high cost permanent that can mimic a key spell, what i am suggesting is really much like this.
I was thinking that instead of adding permanent for an element's defining spells, you could just enhance the spell version. Each element could have only one of those defining cards (darkness could have drain life instead of steal). These cards could possibly be limited to 1 use / turn. The idea behind high cost is to prevent spam and keep it as an option (not replacement of) to cheaper version. IE: 10 quanta buyback deflag isn't always better than 2 quanta deflag. Permanents are vulnerable, i thought it could be nice to have one or two of those undying cards, that would make you feel safe about, in your deck. And i trust this cards could encourage mono / duo decks over rainbow decks.
These spells would increase action taken per turn in the game. As of now, you "pass" frequently without an action, which is not a bad thing and i do believe the game is fairly well balanced. But i thought it could be improved a little; Clicking "done" right away keeps the game faster as it does not bore your opponent, but as you empty your hand, it also lessens your options that you could perform in a turn. These sort of undying spells in your hand would enable an extra action to perform every turn.
An alternative could be less casting cost but depleting your quanta of that color (like miracle). So you could have a 6
buyback deflag which depletes your
quanta on use. (But this favors rainbow over mono)
Ps. Don't mind the examples i gave in OP, the spells and the costs are merely to tell what i meant. I'm pretty sure the costs and choosing which spells to implement can be balanced in practice.
