There are over 800 story events in Exocolonist (and 600,000 words of text), each one a short series of text and choices with various effects. They fall into several categories:
Priority stories[]
These events happen at the end of the month during specific dates in every playthrough, and include your yearly birthday at the end of Quiet-1, the yearly Vertumnalia harvest festival at the end of Dust-1, and the yearly xeno attack at the end of Glow, as well as other major narrative beats.
Character stories[]
These are triggered by talking to a character standing on the map, and include a base repeating event for each one with options to give gifts or unlock cards once your skill is high enough. Milestone friendship events are triggered by reaching each of 10 friendship levels (adults don't have these). Others may be triggered by date or other events in the colony.
Job stories[]
These trigger after choosing which job to do every month (except for exploration) and before the card challenge. They're specific to the job chosen. They're staggered so you only get major job events with choices and card rewards every 2-4 months. After 5-10 events in each job, a final ultimate event will award a high level card.
Location stories[]
Are specific to the location (eg geoponics or garrison) in which the job you're doing takes place. These happen after the monthly job card challenge at intervals of 2-4 months.
Exploration stories[]
These are placed on region maps in the form of question marks or exclamation marks. Some are invisible walls which block your path and must be dealt with before moving further. Most cost 15 stress to pass through, meaning you can at most pass through 6-7 if exploring with zero stress. Some are represented by creatures or other images. Yellow exclamation marks indicate an important event that may be part of a quest line.