Mostly seems to be games where the licensing deal expired or the company folded. I was expecting to see a few more from the adult category that got delisted because someone noticed TOS violating material and reported it.

There was a recent video about Horses, which admittedly was a pre-release, but was technically available for download and is now gone. It is not on this list.

Yeah, brand licensing seems to be by far the most common reason for games to be delisted. A couple of other common ones seem to be:

1) Server shutdowns for multiplayer or live service games

2) Breakdowns of developer/publisher relations

3) A remastered version of the game was released

Idk how common it is anymore, but one game (which seems to be missing from this list) I know was removed from Steam after the early access launch from a Kickstarter campaign. The developers essentially quickly ghosted the game after the EA, considering the Kickstarter complete and taking their money. It was seen as a pretty big scandal in the early days when we had some standards.