Secondary Weapons include handguns, Machine pistols, and Launchers. Lots of high mobility weapons with some heavy vehicle piercing launchers.
Pistols

USP .45
Semi-automatic (single fire).
Unlocked: Default

P99
Semi-automatic (single fire).
Unlocked: Level 10

MP412
Revolver.
Unlocked: Level 30

.44 Magnum
Revolver.
Unlocked: Level 46

Five Seven
Semi-automatic (single fire).
Unlocked: Level 58

Desert Eagle
Semi-automatic (single fire).
Unlocked: Level 76
Machine Pistols

FMG9
Fully automatic, close range.
Unlocked: Default

MP9
Fully automatic, close range.
Unlocked: Level 16

Skorpion
Fully automatic, close range.
Unlocked: Level 36

G18
Fully automatic, close range.
Unlocked: Level 70
Launchers

SMAW
Free fire or vehicle lock-on.
Unlocked: Default

Javelin
Location and vehicle lock-on.
Unlocked: Level 24

Stinger
Vehicle lock-on only.
Unlocked: Level 40

XM25
Airburst 20mm Grenade Launcher.
Unlocked: Level 52

M320 GLM
Grenade Launcher.
Unlocked: Level 64

RPG-7
Fires unguided rockets.
Unlocked: Level 80