Very nice cards, all look nicely balanced. The death one isn't OP due to the fact that while it may gain 4/3 per turn you also lose one 4/3 creature per turn. I love the gravity one especially, been thinking about a gravity creature that could sacrifice itself to buff another card, and almost all the cards look very balanced. One major flaw with some of these and any card suggestion that has to do with things that happen per turn, it adrenaline. It's not the biggest problem for most of these cards, although it would cause the time one to gain +3/+3 for a turn, and then make it interesting as the values change and the number of attacks changes. I guess it's work like dive though.
Also, the problem with Ballistic/Rocket should be solved by the recent Dive/Blessing bug fix. Before, the Dive code probably doubled the creature's attack and then halved it at the end of the turn. Now, I think it doubles that attack, does baseattack-current attack, then adds that value on at the end of the turn. The Buff/Burrow bu is probably fixed by this as well.
Just in case you're interested, I have an Idea about a generic golem (Or a replacement for the Heramite/Steel, although it doesn't fit Earth very well) that would halve it's attack (Rounded up), and then double it at the end of the round. WOuld be meant to be buffed, as (Assuming the starting stats are 4/4) it'd become 2/2, then 5/5 with blessing, and then bump up to a 10/10. May be OP, since it effectively doubles any buff placed on it. It'd be in stasis for the turn you buff it though.
