A few more ideas...
Venom Claws | Toxic Claws
Spell | Spell
4
|3
Target creature's skill is changed to venom.
(Note: Considered having this also poison the target, as Liquid Shadow does, but figured that wouldn't be needed.)
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Twister | Gale
Spell | Spell
4
|3
If target creature's owner has <7 cards in hand, drain
quanta equal to half of target creature's HP and put it in its owner's hand.
(Note: Yeah, may be a bit UP compared to Reverse Time | Rewind, but zanz has said he doesn't want any more removal that doesn't care about the creature's HP. The in-game justification for the quanta drain being based on the HP is that higher-HP creatures are "heavier", therefore it takes more power to lift them. The <7 cards in hand thing is to avoid having a player start their turn with 8 cards in hand. Ratio of drained quanta to creature's HP may need a tweak.)
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Cantrip | Cantrip
Spell | Spell
3 (any) | 2 (any)
(type = other)
If the next card you play this turn is a spell with a cost >0, it becomes your bottom card instead of being discarded.
(Note: Simple idea -- you may eventually be able to reuse the spell, though since it becomes your bottom card, maybe not. It should also help prevent decking, though not quite with the level of effectiveness that Eternity does.)
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Antimagic Field | Delay Field
Permanent | Permanent
7
| 7
[text for Antimagic Field:] When your opponent plays a spell with cost >0, drain
quanta equal to its cost to cancel it, and it becomes the top card of your opponent's deck. Drain
each turn.
[text for Delay Field:] When your opponent plays a creature with cost >0, drain
quanta equal to its cost to cancel it, and it becomes the top card of your opponent's deck. Drain
each turn.
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Diffusion Shield | Diffusion Field
Permanent (Shield) | Permanent (Shield)
5
| 4
Block and count damage from physical sources. At the beginning of your turn, spread that damage between yourself and your creatures.
(Note: To be more specific, the idea is that at the beginning of your turn, the game would loop through an array consisting of you and each of your non-immortal creatures in attack order, doing one damage to the appropriate target, until the damage was all allocated. So, if you have 2 creatures, and you would normally take 5 damage, then when your turn starts, you'll end up taking 2, your first creature will end up taking 2, and your second creature will end up taking 1. I considered having the upped version spread the damage out among both players and their creatures, but figured that might be a bit OP.)