In 1975, guitarist Ritchie Blackmore was becoming sick of the direction his band Deep Purple was taking, so he gave the band his notice and then proceeded to leave to start something new that was more to his liking. This lead him to team up with young singer Ronnie James Dio who was still fairly fresh on the music scene at the time with his blues band Elf. Together, they made three studio albums and one live album packed full of medieval themed hard rock/heavy metal. Dio's powerful vocals that sang of swords and sorcery combined with Blackmore's lightning fast melodic guitar playing and the playing of the other all-star musicians in the band created music the likes of which the world had never heard before or has since. One well known tune that does get airplay on rock stations once in a while is Man on the Silver Mountain.
UFO began in 1969, but did not meet with much success until 1973 when they recruited Scorpions guitarist Michael Schenker, who was only 18 years old at the time but already had a reputation. The addition of Schenker gave the band a distinct edge because not only could he play loud and shred it up, but he could also play more soft and melodic pieces as well. The band would make 4 studio albums and one live album with Schenker in the 70's until he quit in 1978 due to his alcohol abuse. The band would continue on, but would not see anywhere near the success they did with Schenker. One of the most well known songs from this period of the band's history is Doctor, Doctor which does once in a while get some airplay.
Before Sammy Hagar started singing songs like I Can't Drive 55 and Heavy Metal, he was in a band called Montrose, lead by then well known blues rock guitarist Ronnie Montrose. The band began in 1973 when after finishing a tour with Edgar Winter Group Montrose wanted to start something completely new that he would be in charge of. This lead to him being introduced to Hagar by his producer Ted Templeman. Hagar then went to Montrose's house, showed him some songs he had written, and the two instantly got to work. The band would go on to make two albums in its original line-up, though the first album Montrose was more successful. A great deal of tension built up between Hagar and Montrose however and in February of 1975, Hagar left the band. Montrose would however continue on and in the 2000's before Montrose's death the band did reunite a few times. Two of the most well known songs from this era that Hagar still performs to this day are Rock Candy and Bad Motor Scooter.
4. Robin Trower
English guitarist Robin Trower is one musician who does seem to get overlooked quite frequently, unfortunately. However, that is not to say that he is a slouch for he certainly is not. In the 1970's he put out multiple albums with his own style of blues rock which sounded like blues blasted into outer space combined with a bit of Jimi Hendrix technique. He had been in a prog-rock band called Procal Harem until in 1973 he decided to strike it out on his own with bassist/vocalist James Dewar and drummer Bill Lordan. The band has gone through multiple line-up changes over the years, but Trower has remained constant. With Dewar he made some of his most successful albums with current concert staples like Too Rolling Stoned, Bridge of Sighs, Day of the Eagle, and Little Bit of Sympathy.
Before joining Fleetwood Mac in 1974, guitarist/vocalist Lindsey Buckingham and vocalist Stevie Nicks had a folk rock band called Buckingham-Nicks. They were living together and in a relationship at the time, so a lot of their musical chemistry came from that. They did open for some larger named acts like Janis Joplin, Jimi Hendrix, Jefferson Airplane, etc. By 1973 the band was signed to Polydor Records after having moved to Los Angeles and they recorded a self-titled debut album. Unfortunately it was not very successful and has not been released on any format after 1973 despite the duo's success in Fleetwood Mac and as solo artists. The songs are on YouTube and the album is available on Amazon. It is definitely worth the time to listen to them.