There are many bands under the name of Valhalla, 10 of them are metal.
1) The best known Valhalla hails from Petrozavodsk, Rusland and has released one album under the name of "Hail To The Fallen Majesty" in 2003.
2) There is another Valhalla originating from Bedfordshire in England from 1979 playing progressive metal. They had two national single releases on the NEAT records label, "Coming Home" and the double A sides of "Jack" and "Still in Love with You" together with tracks on the compilation album sponsored by the popular music paper SOUNDS. Founding members were MIck Simkins, Ian Parsons, Dave Howard, Ian Glenister, Kev Hunter and Kev Kershaw, later joined by Dave Warminger.
3) One other Valhalla plays thrash metal and comes from Northamptonshire in the United Kingdom.
4) Another Valhalla plays Teutonic War Metal, their latest release was "Defenders of Midgard". They sound very raw, though their music heavily incorporates the use of keyboards.
5) There is another Valhalla group from Spain (Basque Country). Power heavy metal for your ears. Their first demo was made in 1998, "Guardians Of Metal". Their 1st album, "Beyond The Underworld" was made on 2000, the 2nd was "Once Upon A Time" (2001), in 2002 they made "Nightbreed" and their last album was "The Aftermath" (2005).
Their lyrical themes are Fantasy, Vikings, etc.
6) There is another band Valhalla from Ekaterinburg, Russia. Its style can be characterized as forest/black metal. They have released two albums, demo "Wolvish Nocturne" and full-length "Winterbastard" in 2000.
7) There is another band called Valhalla from Sydney, Australia. This band effectively mix a classic rock style with a progressive tinge. Having now disbanded, this group went on to provide members for bands such as super FLORENCE jam and Upfunk Creek.
8) Yet another band by the name of Valhalla hails from Brazil, playing brutal death metal.
Remarkably, this band is all female, and started out in 1989. Their debut full length record "...In the Darkness of Limb" (1994, Sub Way Rock) has a raw production sound reminiscent of early days death metal. The overall sound of the band is very close to a mix of Krisiun and early Sepultura. For being female vocals, they are very brutal and dark, almost guttural grunts. Instrumentally it's a mid-paced groove with great guitar parts which at times sounds black metal inspired.
9) Another band called Valhalla hail from Ukraine and have released one album titled "V Gimnakh I Proklyatiyakh"
10) Valhalla was a heavy metal/grunge band from Trondheim, Norway formed in the early 90's. They released just one album, Rush in 1995. The band split-up in 1997. Three of the members later joined the country rock band The Scarecrows.
11) Valhalla was also a Long Island-based psychedelic/blues band from the late 1960s that featured Mark Mangold. Their sole eponymous album was released in 1969.
12) Valhalla was a RAC band from Hungary.