Check the official artwork and what the skins look like in game here (videos are at the bottom): https://imgur.com/a/R6Nl0Xr or in the folder /skins/gfx/playericons/.
I found the following unused skins:
- NPC_Prometheus_Prometheus_Soldier_Commando (Same model as Scout)
Npc files can be found in the folder /therest/npcs/.
Furthermore the raincoat skin also had an invalid naming convention, as there should be 3 spaces in the file name.
Before: NPC_Civilian_Raincoat (rainsuit).jpg
Fixed: NPC_Civilian_Raincoat ( rainsuit ).jpg
Sadly I couldn't get the plastic bag working in the torture victim's skin.
I also stumbled upon some addition models:
Found some unused skins, fixed the npc files and got them working again.
Check the artwork and videos here (videos are at the bottom): https://imgur.com/a/R6Nl0Xr