So yeah, just some weapons from Halo 2 Anniversary.

You can find the original SFM addons here:
https://steamcommunity.com/sharedfiles/filedetails/?id=2104722136
https://steamcommunity.com/sharedfiles/filedetails/?id=2104733034

Includes:
Halo\UNSC\Halo2A\Weapons\BattleRifle\battlerifle.mdl
Halo\UNSC\Halo2A\Weapons\FragGrenade\fraggrenade.mdl
Halo\UNSC\Halo2A\Weapons\MachineGunTurret\machinegunturret.mdl
Halo\UNSC\Halo2A\Weapons\Magnum\magnum.mdl
Halo\UNSC\Halo2A\Weapons\RocketLauncher\rocketlauncher.mdl
Halo\UNSC\Halo2A\Weapons\Shotgun\shotgun.mdl
Halo\UNSC\Halo2A\Weapons\SMG\smg.mdl
Halo\UNSC\Halo2A\Weapons\SniperRifle\sniperrifle.mdl
Halo\Covenant\Halo2A\Weapons\BeamRifle\beamrifle.mdl
Halo\Covenant\Halo2A\Weapons\BruteShot\bruteshot.mdl
Halo\Covenant\Halo2A\Weapons\Carbine\carbine.mdl
Halo\Covenant\Halo2A\Weapons\FuelRodGun\fuelrodgun.mdl
Halo\Covenant\Halo2A\Weapons\Needler\needler.mdl
Halo\Covenant\Halo2A\Weapons\PlasmaCannon\plasmacannon.mdl
Halo\Covenant\Halo2A\Weapons\PlasmaGrenade\plasmagrenade.mdl
Halo\Covenant\Halo2A\Weapons\PlasmaPistol\plasmapistol.mdl
Halo\Covenant\Halo2A\Weapons\PlasmaRifle\plasmarifle.mdl
Halo\Forerunner\Halo2A\Weapons\SentinelBeam\sentinelbeam.mdl

Credits:
Microsoft/343 Industries- Halo 2 Anniversary
Polingo - Porting to Source Filmmaker.
NeoLin - Ported to Garry's Mod.