Many people believe this Hard Rock/Metal group is only a British or American thing. But in fact there are many other countries around the world, which had their own bands of those genres. Others had commercial success whilst others not.
(In alphabetical order)
1) AC/DC (Australia)
Well, I guess everybody knows them, so description is not needed for this one. Among all their songs, Highway To Hell is perhaps their biggest hit.
2) Acid (Belgium)
One of the few Metal bands during that era, featuring a female vocalist. And perhaps the very first Belgian band that did. Although they weren't commercially successful, they are considered a cult band, at least in their homeland. They released only three albums between the years 1983-1985. What they are doing now, is unknown.
3) Barón Rojo (Spain)
I don't think there's any other known Spanish Hard Rock or Metal band. Spain as a country, isn't much into Rock generally. Anyway, Barón Rojo released many albums during the 80s and some in the 90s as well, sung in Spanish. If I had to choose one, then it would be their debut. Not a bad effort.
4) Bow Wow (aka Vow Wow) (Japan)
A very influential, yet unknown band for most people. Although they never met any commercial success, they inspired many metal bands that appeared during the 80s. Their album Signal Fire from 1977 is definitely their masterpiece, and it's an underrated Hard Rock classic.
5) Europe (Sweden)
Europe were a worldwide phenomenon for a short period of time. During the years 1986 and 1987, their songs The Final Countdown and Carrie were receiving massive airplay all around the world. Their whole album The Final Countdown is a Glam Metal masterpiece, generally.
6) Golden Earring (Netherlands)
Not originally Hard Rock, but since the 70s they developed a Harder sound. Although they are considered superstars in their homeland where they had many Top 10 hits since they started, and in Belgium by some degree, they're known internationally for two songs only. Radar Love and Twilight Zone.
7) Gordi (Yugoslavia)
Well Yugoslavia doesn't exist anymore as a country, but by the time Gordi existed, Yugoslavia did as well. As for the band's works none of them had any commercial success, neitheir in their country nor anywhere else. All their albums were in Serbian language. Pretty bizarre for a Hard Rock/Heavy Metal band.
8. Gorky Park (Russia)
They were perhaps the first Russian band to have some impact in the Western World. And perhaps the only Russian Glam Metal band. Their debut album had moderate success, in the USA as well, including their two biggest hits Bang and Try To Find Me.
9) Hanoi Rocks (Finland)
Short-lived band yet pretty influential. And perhaps is the only known Metal band from the 80s. Also they were one of the few Western bands, that they were very big in Japan. Their best album would be Two Steps From The Move.
10) Kraken (Colombia)
Despite their lack of any significant commercial success, still they made an impact in Colombian music scene generally. Not much impact on the worldwide scene though.
11) Krokus (Switzerland)
They were one of the few European Hard Rock bands, that managed to crack in America. Especially popular during the first half of 80s, they released a series of successful albums, with Headhunter being their most successful among all.
12) Pretty Maids (Denmark)
Pretty Maids had moderate success in some European countries, notably in Germany, but they never became superstars. One of their albums (Future World), managed to make it in the American charts, but not at a good spot (#165). Their most successful song would be Please Don't Leave Me, which is actually a cover of a John Sykes' song released in 1982.
13) Rata Blanca (Argentina)
One of the very few Latin American bands, that have been involved with the Metal sound, as well. It's no surprised they lacked commercial success, not even in their homeland. Maybe if they released some albums in English, they might had some commercial success by some degree.
14) Scorpions (Germany)
Scorpions are definitely the most successful European Hard Rock band. They started to becoming known with their album Lovedrive, although they started more than a decade before its release. Their most successful song is definitely Wind Of Change, reaching #1 in many countries. Apart from their commercial work in the 80s and 90s, their 70s albums before Lovedrive, are definitely cult classics.
15) Sepultura (Brazil)
Perhaps the most successful Latin American Metal-related band among all. I guess the reason was because their songs were sang in English, instead of Portuguese. Although they didn't have any success when they started during the 80s, they met commercial success with their album Chaos A.D. in 1993, in many European countries and in the US as well.
16) Shakin' Street (France)
Commercially unknown band, with only two albums in their discography. Particularly Vampire Rocks and their self-titled album. Both cult Hard Rock classics. Their current whereabouts, are unknown.
17) Thin Lizzy (Ireland)
Definitely the most popular Irish Hard Rock band, and Europe in general. Although they are still active, their golden period ended in 1983, when they disbanded for the first time. Their biggest hit would be The Boys Are Back In Town, which was their only Top 20 US hit, reaching at #12.
18. TNT (Norway)
TNT were definitely one of the most popular bands from Northern Europe during the second half of the 80s. Although, they never became as massive as Europe, they had a good amount of success, especially in their homeland where their album Tell No Tales, reached #1. 10000 Lovers (In One), would be their biggest hit in their career.
19) Triumph (Canada)
They had a streak of successful albums during the 70s and 80s, but unfortunately they never managed to became a classic band. Their most successful albums are Rock & Roll Machine and Allied Forces in Canada and in the US, respectively.
20) Vanadium (Italy)
Perhaps the only known Italian Hard Rock band. Although they never had any commercial success they're known by some degree among Hard Rock/Metal circles in Europe. They had a series of albums during the 80s with Game Over being their most successful one.