Jethro Tull-"The Broadsword and The Beast" (1982)

Framing in the most techno era of the band, which included in addition to this "The Broadsword and the Beast", the album "A" and the later "Under Wraps", it would be a work where the wise mix of hard rock with the sounds of very avant-garde synthesizers, a risky but effective gamble by Ian Anderson.
Without being a concept album to use, the theme of the album leads us to Viking mythologies and Tolkien's tales with acoustic guitars and flutes taking a leading role, combining commerciality with the quality of the songs introduced here.
From the vigorous "Beastie" to the epic "Broadsword", passing through superb songs like "Pussy Willow", the intense "Clasp" or the extravagant "Watching Me Watching You" show an album as forceful as it is commercial that, however, was something despised by his most purist fans.

Jefferson Airplane-"After Bathing at Baxter's" (1967)

The third album of the Jefferson Airplane would mean their most psychedelic work, where they did a great exercise in reflection compared to their enormous and superb "Surrealistic Pillow", without giving the least importance to the fact that it meant a less commercial album.
An album that is full of complex themes and a great diversity of nuances, with melodies that contain a series of diverse and in some cases chaotic sounds.
As proof of this is "The Ballad Of You & Me  Pooneil" which is the perfect demonstration of how surprising this complex but great album is.