Credits: Blue_Slime
Half-Life decorations
If you don't care for visual coherence, the Half-Life decorations addon for Minecraft is a great choice for creating post-apocalyptic scenery. The addon features lots of highly detailed objects, ranging from barrels, containers, and crates to big cranes and signs. All of these elements stand out in a regular game's landscape due to their realistic and decrepit look. For now, there are a total of 158 decorations ready, which is enough to build a thematic map.
Credits: Blue_Slime
Credits: Blue_Slime