Groundbreaking albums. Any genre.

Do.
I’ll go with Ogden’s Nut Gone Flake.   
Mahavishnu Orchestra wasn’t a groundbreaking LP. They toured that before and after. Saw them do play it twice. Saw John again at The Cubby Bear with his guitar synth. Holy Moly.
McLauphlin’s Electric Dreams gets my nod.
Or Adventures In Radioland.
Floyd toured the Dark Side... over a year before they cut it with Alan Parsons. The ground was quite disturbed by then.

Rush Moving Pictures
Pink Floyd The Wall
Tool Undertow (changed prog metal forever)
Yes Fragile
Led Zeppelin 1,2,4, Physical Graffiti 
King Crimson (Agree with above)
Jefferson Airplane Surrealistic Pillow
Jimi Hendrix Are You Experienced...

The list could be somewhat endless as we go through genres.

Elvis Presley-Elvis PresleyVelvet Underground & Nico-The Beatles-Sgt Pepper'sThe Who-My GenerationThe Ramones-The RamonesThe Smiths-The SmithsBlack Sabbath-Black SabbathThe Beach Boys-Pet SoundsMarvin Gaye-What's going onDavid Bowie-The rise and fall if Ziggy StardustMiles Davis-Kind if blueHerbie Hancok-Head hunters.....and many oters
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.....King Crimson-In the court,
Stevie Wonder-Songs in the key if life,
The Byrds-Fifth Dimension, 
Michael Jackson-Thriller,
Pink Floyd-DSOTM,.......

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