I'll mention some Finnish metal festivals for those interested.
Tuska festival, Helsinki
Steelfest, Hyvinkää
Jalometalli, Oulu (did not run last year.. great festival hopefully resurrected this Summer)
..and to end with DIY type doom/stoner festival in Estonia worth checking out. You can see the bandlist at least in their Facebook event page.
Thanks I appreciate your contribution to the article :D