If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.
{1}
Ivory Tower
Artifact
At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.
{4}
Panharmonicon
Artifact
If an artifact or creature entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
{3}{G}{G}{G}
Vigor
Creature - Elemental Incarnation
Trample
If damage would be dealt to another creature you control, prevent that damage. Put a +1/+1 counter on that creature for each 1 damage prevented this way.
When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library.