This is a thread after my own heart - however I despise the term "hair metal" as it's a nonsensical phrase that along with "glam metal" means nothing and is contradictory (though both are very popular across the pond).
Growing up in the 80s I was spoilt: rock was mainstream, all the legends were in their prime (AC/DC, Jovi, Priest, Maiden, Ozzy, Aerosmith, Poison etc) and there were so many bands that many fell through the cracks (or were purposefully ignored as I had such a good choice already). These last few years though, with the help of the internet and You Tube suggestions, I have dedicated myself to discovering all the bands I missed out on. It's given me a real shot in the arm, not only because I wish it was still in the 80s but because I get to discover new music despite it being 20+ years old.
The sad thing is, for me, is that the tail-end of the genre: 89-93 produced the best work. For most of the 80s, bands were either heavy and not-so-melodic or lightweight and catchy as hell but with albums like Skid Row, bands were merging the two and building on the huge production values of Whitesnake's 1987 - generating albums of cranked guitars, booming drums and choruses that sound like they're chanted by 1000 people.
Anyway, enough of the waffle, here are some killer bands I've found on top of the great names mentioned already We'll start with my fave discovery Baton Rouge. Also special mention to Dare for creating a masterpiece album (Blood From Stone) without a single weak track:
BATON ROUGE
DARE
WILDSIDE
KATMANDU
TYKETTO
SAINTS AND SINNERS
SIGNAL
EVENRUDE
NO SWEAT
LIONSHEART
FM
BLUE TEARS
LEE AARON
WITHOUT LOVE
CHRISSY STEELE