Containers are anything on a map you can inspect for semi-random loot (unlike seeing a wood plank which is always a wood plank). While some containers are unique, many are found on various maps and often contains semi-specific loot.
If you inspect a container and depart from the zone (city), all its unextracted contents will vanish. Switching floors doesn't count as departing from the zone, but crashing out or relogging does.
Support kits can presently only be found in various containers (and not in drops from killed infected).
You can find locations for each container on their respective pages.
|Guitar case||Average||Contains various intruments|
|Gun bag||Average||Guns and bows|
|Locker||Average||Sometimes||Items for common resources (plastic, wood, metal), some items for rare resources (precious ore), beverages and pastries|
|Safe / Wall safe||High||Often||Swords, guns, alcohol, rarer items.|
|Sword case||Average||Sometimes||Various bladed weapons, including the more valuable swords.|
|Vending machine||Average||Sometimes||Beverages and pastries|
|Fish tank||Various fish|