I'm such a wimp. I can't possibly narrow down a selection of albums from the 70s. That was my formative decade and I have thousands of albums that I enjoy so much I can't even begin, sorry.
I love the early 70s 'leftover' rock from the 60s, then got into progressive rock ala King Crimson, PFM, Gentle Giant, Yes...then progjazz like Mahavishnu Orchestra, Return to Forever, Weather Report etc., then punk/new wave as it developed toward the later half of the 70s, and much of the funk/before disco. I guess if I HAD to pick ONE favorite it would have to be King Crimson, their whole catalog from that decade. I'm not familiar with much of what I read here, what I would term avant garde/obscure/eclectic.
One recurrent band I enjoyed that was FAR from the mainstream and mentioned here quite frequently is Can. I do have about 1/2 of what I see listed here, the more 'familiar' listings. Then I've got some relatively odd ones I don't see here like Grin, Brand X, The Pink Fairies, Gryphon, John Abercrombie, Dixie Dregs and more....I'm surprised I didn't notice any Mott the Hoople, "All the Young Dudes".