I have been wondering if there was a public website where you could seek names of games to see who currently owns the rights.I suppose when the rights of a game are bought there is a track somewhere but if you don't live in the country where the game was bought it might be hard to figure, even more, when it is about old games.
I often contact directly developers of said games to ask them, but it is not always easy.
Unless developers push that information out, there is no easy way to discern that from the outside (unlike, say, trademark registrations or company ownership). Ownership of individual game rights might be vested in individual employees, publishers, acquiring entities, IP purchasers, IP holding companies, investors, debtors - it really depends on what deals were done and the fate of the original company.
On top of that complexity, there may be split rights between for a game where one entity owns the IP and the other owns the underlying tech. And also there are instances where multiple companies share the rights, participate in derived revenues, or need to provide approval for anything that happens to it.
I've tried tracking down the rights to a couple of games from the 80s that I was interested to remake, and it was a mission that ultimately ended up being "too hard".