The breaking point is tricky here, when do we say the Norwegian sound fell into disarray and began getting eclipsed by those initially influenced by them? 1996, 1997, 1998? Abigor always had its unique spin on the genre, same goes for Sigh. Blut Aus Nord was releasing interesting stuff as far back as 1995, Beherit and the Swedish bands were around too, the fledgling American sound, and many more examples abound.
A 1997 example which comes to my mind though is
https://www.youtube.com/watch?v=VA_IWmvDZko. In many ways this album paved the way for the East European version of the genre, which emphasized the incorporation of Slavic, Finnish, and Romanian folk instrumentation and motifs.
Also in 1997 some of the original Norwegian bands were either in radical transition (Ulver, Satyricon), defunct (Burzum), in disarray (Immortal), or all of the above (Mayhem). Meanwhile, with Samoth out of prison, Emperor returned with Anthems to the Welkin in mid 1997, one of the biggest selling, and most popular black metal albums of all time. But I think it serves as the perfect bookend to Norwegian dominance of the genre, whether one likes, loathes, or loves that album (I like it). And Emperor, Darkthrone and Enslaved would also soon be moving further away from their original sounds too.
So I'm using top BM albums since Anthems was recorded (if any of you guys want to come up with another break point, please do, just tell us why: the more opinions the better). Also aiming for a list of 15, because otherwise I will go on for too long, but you want to put down 10 or 20, go for it.