This is not really a guide, just a depot that contains a lot of useful CoD: Online assets for Black Ops modding.
I'm not sure this section is correct, or should be moved - we'll see

Sherkan: Online Warfare (also used to be called Sherkan SE5) was another standalone multiplayer Modern Warfare 2 russian-only client. It was cancelled.
Anyways, it had a lot of interesting stuff from Call of Duty: Online.

So, here it is, the ultimate Black Ops modding depot.
Folder Link: https://mega.nz/#F!2p9GCS5K!IUl_eSkFaBtjbhOrLfY9hg

Contains:
- Call of Duty: Online Weapons, Animations, Images and Sounds
- FreeReign Studio, Escape from Tarkov and STALKER models
- Original Left 4 Dead 2 and Insurgency Weapon Sounds
- All Weapon Sound Mods from Garry's Mod, Left 4 Dead 2 and Insurgency Workshop Hubs
- Female Voice Soundpack for MW2 (should be reappliable for other CoDs)
- and much more!