When Queen released their first album, most of the attention they got from the media was focused on Brian May and the fact he made his own guitar (with his father). Freddie Mercury gradually developed both his songwriting and his stage persona to the point that he became the face of the band, at least as far as most of the public was concerned. Bassist John Deacon and drummer Roger Taylor were almost always overshadowed, but they still had their moments: John scored three big hits for the band in 1975, 1980 and 1984, and Roger also wrote some big numbers from 1984 onwards. In fact, a lot (though not all) of the band's big hits from 1980 onwards were by either one of them and by 1989 the band were crediting all songwriting to all four of them, effectively becoming an Ensemble Cast.
When The Beach Boys' Brian Wilson suffered an emotional breakdown in 1965 and decided to quit touring with the group, Bruce Johnston (previously of Beach Boys soundalike group the Rip Chords) was hired to take over his role playing bass onstage. By the end of the year Johnston was joining the Beach Boys in the studio and later became an integral part of their late '60s/early '70s recordings, even writing songs like "Disney Girls" for them.
Moreso Dennis Wilson, who went from being the under-appreciated drummer to writing such classics as "Forever", to the point that his solo album, "Pacific Ocean Blue", charted higher and was more critically acclaimed than the Beach Boys album released that same year.
Dennis Wilson is even more surprising because he was seen as the jockish surfer who had no time for music, and yet his songs eventually showed him to be an emotional, troubled person just like his brothers. Of course, his time with Charles Manson changed his personality for the worse.
Ringo Starr was a late replacement into the band and widely considered (however fairly) to be their least talented member. Furthermore, he was the least conventionally handsome of the group and, as the drummer, held the least glamorous position in the band. Despite all this, his goofy charm and approachable good looks earned him the most fan mail of any Beatle.
George Harrison was arguably the least popular Beatle during the band's run. He was not a part of the singing/songwriting superduo of Lennon-McCartney, nor did he have the charm of Ringo and was known for being quiet and moody. However, immediately after the band broke up he was the first of the four to score a #1 hit, and his album All Things Must Pass is to this day the top selling album by any solo Beatle. His ballad "Something" is also the second most frequently covered Beatles song after "Yesterday," and even John Lennon once remarked, "It's the best damn song on the whole album." Harrison seems to have been well aware of his dark horse status. He had a minor hit with the song "Dark Horse," and his custom record label was called Dark Horse Records.
Bone Thugs-n-Harmony is a group example. As they emerged during a era of hip-hop where you had to be either from the west or the east to make it in that particular field. Not only did they not hail from either coast, but hailed from the Midwest (Cleveland to be precise), and managed to have 3 back to back multi platinum records amidst the hype and controversy of the then bi-coastal feud between the east and west.
Despite being the bassist/lyricist of Fall Out Boy, Pete Wentz served as the front man forFall Out Boy up until their hiatus (or their breakup, depending on who you talk to). Conventionally, either the lead singer/rhythm guitarist, Patrick Stump or the founder of the band, lead guitarist Joe Trohman should've been the front man, but seeing as Patrick didn't fit the standard front man mold and neither Joe or the drummer Andy Hurley had any interest in being the face, the role went to Pete. Considering his long standing mental health issues and relationship woes around the time of Fall Out Boy's height of popularity, it's questionable if this was the right decision in the long run. One is just as likely to find people citing his dislike of his role as one could find people thinking he revelsin it. His massively prominent fandom/fandumb is a common conversation topic among Fall Out Boy fans and music spectators. Wentz's scandalous notoriety is lampshaded in the music video for "This Ain't a Scene, It's an Arms Race" from Infinity on High and often lampshaded by the band and himself. The transition of his side project Black Cards from a more poppy/dancey band with a female lead singer to an EDM duo with the previous incarnation's drummer looks to be a deliberate attempt to avoid this trope a second time around with another group.
Patrick Stump, however, still remains a popular member of Fall Out Boy and while his solo album "Soul Punk" wasn't a financial success, various music spectators and fans of Fall Out Boy (that is, those who didn't automatically dismiss it for not being Fall Out Boy) found it to be a pleasant surprise and an indicator of the long introverted singer coming out of his shell. Patrick also has a habit of unintentionally overshadowing other bands when he does guest vocals for one of their songs.
Joe Trohman and the drummer, Andy Hurley get this through their involvement with the hard rock supergroup The Damned Things, by virtue of being the most recognizable band members outside of Scott Ian. The group is both disliked by hard rock/metal fans for having members of Fall Out Boy in it and disliked by Fall Out Boy fans for being harder than/not being Fall Out Boy. Then you have those that just like it.
Again for Joe Trohman with his other side project With Teeth, mainly due to him unexpectedly providing lead vocals. Heck, Andy and Joe's sideprojects are probably darkhorses among the Fall Out Boy fanbase compared to Patrick and Pete's based on The Damned Things' album being available much sooner compared to Soul Punk and Black Cards' original release.
Similarly, Aaron Gillespie, drummer/secondary vocalist of Underoath, is decidedly more popular among the young females of the band's fanbase than frontman Spencer Chamberlain, due to his angelically emotive vocals (in contrast to Chamberlain's agonizing growls) and attractive red hair. He has even spawned his own spinoffone-man band The Almost.
The Almost was so successful that he left Underoath to focus on it.
The Story of Evil series features the evil princess' very literal horse named Josephine mentioned only once in the whole series. A lot of fans' reaction after watching the series is, "Yeah but what happened to Josephine? We need to know!"
Apparently Gakupo kidnapped her for his harem in Venomania.
Copeland was the leader of the band when they formed, he also played most of the guitar parts on both tracks on their first single Fall Out/Nothing Achieving (Henry Padovani only played the solos), tracks he also wrote entirely himself. Copeland also recorded his own solo material (under the name Klark Kent) entirely by himself.
Andy Summers was no slouch either, responsible for much of the band's jazz influence and wackier elements, but he was overshadowed by the other band members.
Ace Frehly of KISS earned himself a loyal following, not just for his flashy lead guitar playing, but for his cool, cocky attitude that was a welcome change from the off-putting, egomaniacal ham of Greedy Jew Gene Simmons and Casanova Wannabe Paul Stanley. The fact that he had the most successful solo career out of all the members further cements this status.
Normally the face of the band is the lead singer, but while Simon Le Bon got plenty of attention, the other members of Duran Duran found themselves with their own fan groups (even the unconventionally attractive lead guitarist Andy Taylor). In fact, bassist John Taylor (whom some considered as eclipsing Le Bon in the attractiveness stakes) pointed this out by stating the band were "like a box of Quality Street [chocolates] — there's something for everyone". And speaking of John Taylor, he was perhaps the darkest of all dark horses, considering that he spent his childhood and adolescence being a shy, withdrawn nerd who wore glasses, was into wargaming, and got little attention from the opposite sex. Being the lead guitarist of his first band boosted his confidence a little, but forming Duran Duran and the local attention the band got in the very late 1970s was what drew him out of his shell.