Visual novels, and interactive fiction come to mind as things that are video game adjacent but aren’t necessarily games. Most of the first category I’ve encountered are either porn, horror, or… both – though they can be about anything the author wants to write about, of course, and the relative accessibility of the medium means people have pushed it in a lot of directions even though it’s kind of niche.

Interactive fiction includes things like text adventures and choose-your-own-adventure books. Most of the computer-based ones I’ve encountered involve traversing a node-graph of locations, manipulating items, and solving puzzles – though the gaminess varies a lot depending on the specific title. They’re even more niche nowadays, but people still make and play/read them.