Light producing items that you carry and still produce lights, work like torches in Terraria.
Some block besides water that negates fall damage entirely.
More water-based mobs
More farming and fishing options and results.
Ways to lock doors, chests, furnaces and whatever else without using server mods.
Decorations besides paintings.
Light-producing item that can be hung on ceilings (besides glowstone). Maybe a candelabra?
EDIT: Oh yes, and:
Armor that completely negates fire-based damage
Boots that prevent the user from taking fall damage
Some block besides water that negates fall damage entirely.
More water-based mobs
More farming and fishing options and results.
Ways to lock doors, chests, furnaces and whatever else without using server mods.
Decorations besides paintings.
Light-producing item that can be hung on ceilings (besides glowstone). Maybe a candelabra?
EDIT: Oh yes, and:
Armor that completely negates fire-based damage
Boots that prevent the user from taking fall damage