Add additional fuel resources
Wood gets boring
Add resources such as natural gas, oil, coal, etc. which could be scavenged or harvested. Heck even Mist gas could be fun. Different fuels would last longer when used to fuel fires. Could add different canasters that could be crafted to hold the different fuels. Could be used to craft fire based weapons, different types of food with better effects, power other types of buildings, or added to crafting recipes to add or affect them differently.
Also... Craftable solar panels that can power lights and scavenged street lamps