I decided to note down all the loot that i got from 50 cubelets to see what i would get, and to see which items are more common than others. Here's everything that i received in order. Sorry for any typo's, i haven't actually checked this log since about 30 cubelets.
Cubelet 1 = Legendary: Orange Glass
Cubelet 2 = Common: Red helmet
Cubelet 3 = Uncommon: Purple helmet
Cubelet 4: Rare: Water drip trail
Cubelet 5: Rare: Pink hat
Cubelet 6: Common: Chest hat
Cubelet 7: Rare: Orange chestplate
Cubelet 8: Common: Pumpkin hat
Cubelet 9: Common: Lava bucket trail
Cubelet 10: Rare: Orange Chestplate
Cubelet 11: Common: Red legs
Cubelet 12: Common: Melon hat
Cubelet 13: Common: Blue chestplate
Cubelet 14: Common: Blue legs
Cubelet 15: Common: Pumpkin hat
Cubelet 16: Uncommon: Purple leggings
Cubelet 17: Uncommon: TnT hat
Cubelet 18: Common: Red legs
Cubelet 19: Uncommon: Purple boots
Cubelet 20: Rare: Cave Spider hat
Cubelet 21: Common: Cake hat (Finally)
Cubelet 22: Common: Zombie hat
Cubelet 23: Common: enderman hat
Cubelet 24: Uncommon: TnT hat
Cubelet 25: Rare: Cave spider hat
Cubelet 26: Common: Chest hat
Cubelet 27: Rare: Pink helmet
Cubelet 28: Rare: Water drip trail
Cubelet 29: Common: Spider hat
Cubelet 30: Rare: Water drip trail
Cubelet 31: Rare: Water drip trail (Are you kidding me?..)
Cubelet 32: Common: Water drip arrow trail
Cubelet 33: Uncommon: Green chestplate
Cubelet 34: Common: Water drip arrow trail
Cubelet 35: Rare: Toxic waste trail (Finally)
Cubelet 36: Common: Lava drip trail
Cubelet 37: Common: Zombie hat
Cubelet 38: Uncommon: Green leggings
Cubelet 39: Common: Red boots
Cubelet 40: Common: Green boots
Cubelet 41: Common: Enderman hat
Cubelet 42: Rare: Water drip trail
Cubelet 43: Uncommon: Green boots
Cubelet 44: Common: Red boots
Cubelet 45: Common: Lava drip trail
Cubelet 46: Common: Pumpkin hat
Cubelet 47: Uncommon: TnT hat
Cubelet 48: Rare: Wither boss hat
Cubelet 49: Common: Chest hat
Cubelet 50: Common: Red boots
It became very obvious to me that 'legendary' ranked items are very rare. I only got 1 out of all 50 cubelets, and that was my first cubelet.
Cubelet 1 = Legendary: Orange Glass
Cubelet 2 = Common: Red helmet
Cubelet 3 = Uncommon: Purple helmet
Cubelet 4: Rare: Water drip trail
Cubelet 5: Rare: Pink hat
Cubelet 6: Common: Chest hat
Cubelet 7: Rare: Orange chestplate
Cubelet 8: Common: Pumpkin hat
Cubelet 9: Common: Lava bucket trail
Cubelet 10: Rare: Orange Chestplate
Cubelet 11: Common: Red legs
Cubelet 12: Common: Melon hat
Cubelet 13: Common: Blue chestplate
Cubelet 14: Common: Blue legs
Cubelet 15: Common: Pumpkin hat
Cubelet 16: Uncommon: Purple leggings
Cubelet 17: Uncommon: TnT hat
Cubelet 18: Common: Red legs
Cubelet 19: Uncommon: Purple boots
Cubelet 20: Rare: Cave Spider hat
Cubelet 21: Common: Cake hat (Finally)
Cubelet 22: Common: Zombie hat
Cubelet 23: Common: enderman hat
Cubelet 24: Uncommon: TnT hat
Cubelet 25: Rare: Cave spider hat
Cubelet 26: Common: Chest hat
Cubelet 27: Rare: Pink helmet
Cubelet 28: Rare: Water drip trail
Cubelet 29: Common: Spider hat
Cubelet 30: Rare: Water drip trail
Cubelet 31: Rare: Water drip trail (Are you kidding me?..)
Cubelet 32: Common: Water drip arrow trail
Cubelet 33: Uncommon: Green chestplate
Cubelet 34: Common: Water drip arrow trail
Cubelet 35: Rare: Toxic waste trail (Finally)
Cubelet 36: Common: Lava drip trail
Cubelet 37: Common: Zombie hat
Cubelet 38: Uncommon: Green leggings
Cubelet 39: Common: Red boots
Cubelet 40: Common: Green boots
Cubelet 41: Common: Enderman hat
Cubelet 42: Rare: Water drip trail
Cubelet 43: Uncommon: Green boots
Cubelet 44: Common: Red boots
Cubelet 45: Common: Lava drip trail
Cubelet 46: Common: Pumpkin hat
Cubelet 47: Uncommon: TnT hat
Cubelet 48: Rare: Wither boss hat
Cubelet 49: Common: Chest hat
Cubelet 50: Common: Red boots
It became very obvious to me that 'legendary' ranked items are very rare. I only got 1 out of all 50 cubelets, and that was my first cubelet.