Do anyone know of any Linux exclusive titles made?
Many early games were indeed exclusive to their unix. Until they were ported.
I highly doubt you will find many actual games that are exclusive for non trivial reasons. The most trivial is that no one ported it. But if you use open source libraries, you will be hard pressed to find linux exclusive libraries.
Maybe some games of idealists. But those are also likely to have open source, making exclusiveness moot.