Chaos Sliver: I guess 2 Entorpy for CS is a good cost for it on suchaweak creature. Still, I'd make it 3.
Poison Sliver: Is good.
HevE Sliver: Is good, although... 6 of those and you have 6 14/14 creatures. Still, the cost should be enough.
Armor Sliver: I alright.
Healing Sliver: Not very useful, as all those seem like they'd die fastly if any, but. Maybe increase the effect radius to all creatures and/or give a +1/+1 buff to all.
Wepon Sliver: Drop the cost to 2. 3 isn't that needed. Or is it? I'm not sure. Leave it as it is.
Purity Sliver: The first ability is just Plagueproofness, what is kinda alright, just pisses them off, the second one wrecks any poison deck, as you can heal all the poison off you every turn. Change the concept entirely.
Holy Sliver: If only until the end of turn, 1 Light for this is alright.
Diving Sliver: Not only it replaces the original useful abilities, but also is a 1:1 ratio damage? Notverygood. Make it a honest dive, or just a stable boost.
Quicksilver: This one is actually pretty strong. Would be very useful, if not a bit too strong in Time/Gravity Sliders.
Vampire Sliver: Sounds good. High cost, but makes all of them gain +1/+1 if they don't run into a full stop or a Sundale.
Immortal Sliver: This one could be a bit too strong. Having all those Sliders sounds good, but having them un-get-riddable-of sounds just OP.