The tag thoughts is for short text posts. You can combine it with other tags (by going down that page and clicking/tapping on other tags) to find my thoughts on specific games or topics.
The tag reviews is for reviews of games that I played through. The tag milestones is for tracking total play time and completed games.
A special tag acnhootd is reserved for the outfit of the day in Animal Crossing: New Horizons. You can also directly see them all on the OOTD page, though that might take a while to load.
Here are the game specific tags: