Events
Events could be timed based, triggered, or randomly invoked.
Event types
Timed event
In 7 days to die you have two timed events: every night zombies attack, and every 7 days you are swarmed with zombies. Timed events here are similar, and I suggest we even have the same kind of events. Perhaps the nightly hordes coming can be irregular, and maybe not as explicit but mainly that during night Zombies are more active and cluster together more, which makes nightly loot trips a lot harder.
The 7 day timed event could be a progression event that opens up the next area or whatever.
Extraction event
When roaming you could come across something larger that you'd like to salvage or use, e.g. a truck. You can loot some parts of it always, but if you are a gatherer/disassembler/looter by profession you can salvage more type of items and in larger quantites. You can also initiate a extraction event where you need to defend the truck against for a certain amount of time while you have companions coming in to salvage it.