There are a lot of different items and weapons you can unlock in Bioshock 2 when playing in multiplayer. Every rank has at least one unlockable, and quite a few have anywhere from two to four unlockables.
Here is the complete list of items you can unlock in Bioshock 2 Multiplayer.
Rank 01 – Mask: Rabbit/Goat/Pink Feather
Rank 01 – Melee: Wrench/Candle Stick/Pipe
Rank 01 – Plasmid: Electro Bol/Winter Blast/Incinerate
Rank 01 – Weapon: Pistol/Shotgun
Rank 02 – Weapon: Machine Gun
Rank 03 – Tonic: Expert Researcher/Security Evasion
Rank 04 – Plasmid: Air Dash
Rank 05 – Upgrade: Pistol Automatic Firing
Rank 06 – Weapon: Grenade Launcher
Rank 07 – Tonic: Speedy Recovery/Eve Saver
Rank 08 – Plasmid: Geyser Trap
Rank 09 – Upgrade: Shotgun Rate of Fire
Rank 10 – Mask: Eagle/Tragic Comedy
Rank 10 – Melee: Machete/Rolling Pin
Rank 10 – Weapon: Crossbow
Rank 11 – Tonic: Back Stabber
Rank 12 – Plasmid: Telekinesis
Rank 13 – Upgrade: Machine Gun Magazine Size
Rank 14 – Weapon: Nail Gun
Rank 15 – Tonic: Metabolic Eve
Rank 16 – Plasmid: Houdini
Rank 17 – Upgrade: Grenade Launcher Homing Grenades
Rank 18 – Weapon: Elephant Gun
Rank 19 – Tonic: Sabotage
Rank 20 – Mask: Moon/Indigo Feather
Rank 20 – Melee: Mallet/Barbed Wire
Rank 20 – Plasmid: Insect Swarm
Rank 21 – Upgrade: Crossbow Damage Increase
Rank 22 – Tonic: Repairman
Rank 23 – Upgrade: Nail Gun Magazine Size
Rank 24 – Upgrade: Speedy Hacker
Rank 25 – Upgrade: Elephant Gun Sniper Scope
Rank 26 – Tonic: Slugger
Rank 27 – Upgrade: Pistol Damage Upgrade
Rank 28 – Tonic: Leg Up
Rank 29 – Upgrade: Shotgun Automatic Reload
Rank 30 – Mask: Peacock Feather/Sun God
Rank 30 – Melee: Crowbar/Flashlight
Rank 30 – Tonic: Fast Feet
Rank 31 – Upgrade: Machine Gun Kickback Reduction
Rank 32 – Tonic: Deadly Machine
Rank 33 – Upgrade: Grenade Launcher Velocity Boost
Rank 34 – Tonic: Headhunter
Rank 35 – Upgrade: Crossbow Rate of Fire
Rank 36 – Tonic: Big Game Hunter
Rank 37 – Upgrade: Nail Gun Damage Increase
Rank 38 – Tonic: Death Trap
Rank 39 – Upgrade: Elephant Gun Damage Increase
Rank 40 – Mask: Octopus/Demon
Rank 40 – Melee: Hatchet
Rank 40 – Tonic: Resurrection
