One is a Slovenian indie rock band formed in 1994 in Ljubljana, Slovenia. The band released two studio albums, "Pop Sux" (2001) and "Neotonia" (2004), before disbanding in 2005.
Another is a Japanese rock band formed in 2001. They have released six studio albums, including "Genesis of Next" (2002), "The Answer" (2004), and "Music Meister" (2010).
There are also several other bands and musical groups that have used the name "Pop", but these are the most notable ones.