Druid spells I like are Longstrider, Faerie Fire, Summon Swarm, Chill/Heat Metal, Soften Earth&Stone, Giant Vermin and Rusting Grasp. They are versatile and useful, especially in a dungeon. E.g. with Rusting Grasp alone you can "disarm" traps, "open" doors, free yourself from handcuffs etc.