Mastodon
Unlike most other bands on this list, Mastodon has released a bunch of records. One throughline of their work is the lack of throughline. The band is a metal group, sure, but what kind of metal they want to be from album to album differs. Few groups have so cerebrally approached each record with a certain theme and then the ability to create such wonder based off the original idea.
Their second album, 2004's Leviathan, is based on the novel Moby Dick. The album was featured on several best-of lists from albums released in the 2000s. The record represents what Mastodon does best, though, in that they produced full works of art instead of going for random singles of success.
The other wonder is that the band isn't afraid to have guest singers take lead vocals at times. Mastodon is focused on how the overall music sounds and the vocal performance is simply another instrument. So when Queen of the Stone Age's Josh Homme sings on "Colony of Birchmen" it's all just part of the arch of perfection which the band has maintained over eight albums.
The Smiths
The Smiths only produced four studio albums from 1984 through 1987. Morrissey did not like the record company and the rest of the band mostly did not care for him. Even nearly forty years after the final record, all that remains true. What is also true is that the Smiths produced some of the greatest records of the 1980s and influenced a multitude of bands, and their absence from the Rock and Roll Hall of Fame is criminal.
There are simply too many singles from the band's four albums to list here. In fact, there are zero bad songs, even on the many versions of B-Side releases. Each features the biting lyrical poetry of Morrissey and the guitar brilliance of Johnny Marr. That these two cannot get along and make new music now is a shame.
The group's masterpiece is their third album, The Queen is Dead. The record features one of the greatest tracks humankind is capable of producing, "There is a Light That Never Goes Out" but also features "Cemetry Gates." The album is the best example of how the Smiths could never quite be equaled by any band that wanted to be like them: The craftsmanship is simply too high.