How about a thread about a musician you discovered and liked and it turned out that they are actually extremely popular somewhere but you never heard of them before.
For me it was Hyde. Love his album Anti:
And turned out he has pretty much godlike status in Japan. Actual name is Hideto Takarai and sold more than 40 million records with the group L’ Arc en Ciel. Was also part of a group called Vamps and has some albums under the name Hyde.