1. Models of enemies. https://www.unrealengine.com/marketplace/en-US/product/undead-pack-01
2.  
3. Models of human NPCs. https://www.unrealengine.com/marketplace/en-US/product/9c3fab270dfe468a9a920da0c10fa2ad
4.  
5. Verbal sounds from all characters. https://www.unrealengine.com/marketplace/en-US/product/human-vocalizations
6.  
7. Most non-verbal sound effects. https://www.unrealengine.com/marketplace/en-US/product/interface-item-sounds-pack
8.  
9. Background building textures. https://www.unrealengine.com/marketplace/en-US/product/modular-building-set
10.  
11. Assault Rifle. https://www.unrealengine.com/marketplace/en-US/product/military-weapons-dark
12.  
13. Civilian vehicle props. https://www.unrealengine.com/marketplace/en-US/product/bbcb90a03f844edbb20c8b89ee16ea32
14.  
15. Military vehicle prop. https://www.unrealengine.com/marketplace/en-US/product/mrap-oshkosh-west
16.  
17. Pick-up indicator. https://www.flaticon.com/free-icon/glove_1106960?related_id=1107149&origin=search
18.  
19. Background music. https://www.purple-planet.com/tracks/grease-monkeys
20.  
21. A building texture. https://opengameart.org/content/buildings-batch-of-21-seamless-textures-with-normalmaps-verticlebrownbrickssjpg
22.  
23. A building texture. https://freestocktextures.com/texture/facade-of-building-with-plenty-windows,867.html
24.  
25. A building texture. https://www.pexels.com/photo/beige-and-blue-tiled-surface-845234/
26.  
27. A building texture. https://hotcore.info/babki/building-texture-seamless.htm OR https://hotcore.info/act/kareff-030627.html
28.  
29. The crosshair. https://www.youtube.com/watch?v=g8G0BcKkpck&list=PLQN3U_-lMANP2_B1RPw7QDJ8Ja4aWKKg3&index=4&ab_channel=MattAspland