These are all of the skills that every character in the Druid class learns.

Block - Already learned
Melee Attack - Already learned
Sting - Already learned
Nature's Medicine - Level 3
Endurance - Level 5
Thorny Decoy - Level 5
Mend Wounds - Level 8
Stone Storm - Level 8
Clinging Vines - Level 10
Breath of the North - Level 10
Tranquil Thoughts - Level 13
Cloak of Thorns - Level 15
Thunder Strike - Level 15
Quake - Level 18
Tempest - Level 20
Cleanse the Land - 25