There's a standardized laundry list of bands that gets tossed around as proto-punk: the Velvets, the Stooges, the Modern Lovers—even prog-rocker Peter Hammill sometimes makes the cut. To that list, I'd add Yoko Ono.
Once reviled as the anti-Beatle that ruined everything—which was of course, preposterous, Yoko Ono has run a lifelong gauntlet of bullshit. Her marriage to John Lennon provided her enormous opportunities, but also brought her art to the attention of people that had zero context or desire to understand or engage with it. She was used as a bad punchline for art-rock jokes. Lately, as rock itself has moved out of the mainstream (again) and it's veered in artsier directions, she's been enjoying a bit of unexpected, elder stateswoman status. Big names are lining up 'round the block to collaborate with her.
If you go back to her solo work in the early 70s, Ono makes a great case for her status as a punk rock progenitor. Those albums feature strident, socio-political lyrics over songs squarely based on barroom blues—sounding off-the-cuff without much of any concern about the 'right' way to play or sing it. That's about as good a description of the early punk albums as I can think of.
The song driving this all home, for me, was I Felt Like Smashing My Face in a Clear Glass Window off 1973's Approximately Infinite Universe. The title alone is punk as fuck. Over a slopped, funky blues riff, Ono muses about self-determination and escaping from her parents' (and by extension, society's) expectations. While the feminist implications are obvious, It's reach is well beyond, tapping into a vein of pure teen angst—the universal desire to come of your own age; the fount of all things punk rock.
While songs like Clear Glass Window certainly presaged punk, in many ways, Yoko Ono is also a proto-post-punk artist (if you can stomach such an oxymoron). When her more outré tendencies collided with popular rock forms, as on Don't Worry Kyoko (Mommy's Only Looking for Her Hand in the Snow) she helped clear a path for the utter dismantling of rock-n-roll's structures from within that would happen in the post-punk era.