The Action, Rolled Gold (1968/2002)
The Action were a second-tier British Invasion act, with a number of minor R&B and pop singles comparable to (but not nearly as compelling as) contemporaneous hits from the early Stones, Pretty Things, and Small Faces, later joining their counterparts with some mild psychedelia.
Between 1967 and 1968, they recorded over a dozen demos, apparently for an album to be produced by Beatles producer George Martin, but the songs were never finished and were stashed in a vault for decades. (In the meantime, after a few personnel changes, the band changed their name to Mighty Baby and issued a few albums of sprawling psychedelia reminiscent of Traffic.)
The demos were finally packaged as Rolled Gold in 2002. And they're far better than anyone could have expect from this band. There are at least half a dozen songs that are as good as anything the Who or the Stones or the Kinks were doing at that time, wonderful pop hooks, killer guitar riffs, and the sort of choruses that will leave you with your jaws open. As one might expect from the era, there is some psychedelic trippiness, but there is also a strain of power pop that sees the band anticipating artists like Big Star and the Raspberries (not to mention later mod acts like The Jam).
Album opener "Come Around" is a perfect late 60s anthem, an earnest flower power ode but with a punchy Who-like riff; it's followed by the similarly anthemic "Something to Say," again perfectly encapsulating a late 60s message of hope and self-affirmation. Later you've got "Strange Roads," with a guitar riff other bands would kill for; the more obviously psychedelic but astoundingly great "Brain"; the throwback to their earlier period "Look at the View"; the sweetly poppy "Climbing Up The Wall"; and finally the moody "In My Dream," which was indicative of the jammier direction they'd take as Mighty Baby.
Unfortunately, as these are demos, the sound quality isn't perfect; the songs are all mono, with some rough edges and muffed notes. But you can close you eyes and imagine what might have been with some real production; I'm confident this would be spoken of the same way classic rock buffs speak of The Who Sell Out or the Small Faces' Ogdens' Nut Gone Flake.
Obviously no video of the band performing this material, but here's some random footage for "Strange Roads":