I’ll link to Two old threads and repost mine: Awesome cover songs? - #13 by What_Exit
In a related thread Your favorite ‘non-traditional’ cover of a hit song? I mentioned Yes’s cover of America (written by Simon & Garfunkel) is much, much better. Here it is live in all of its 11 minutes of Glory!
I love Fiona Apple’s Across the Universe. is very special.
Jimi Hendrix’s All along the Watchtower is great and Dylan said it was the best version he ever heard.
Led Zeppelin did “Babe I’m Gonna Leave You” that was recorded by Joan Baez in 63 but apparently written by Anne Bredon in the late 1950s.
Weird one: Barbra Streisand–Somewhere cover of the Broadway tune from West Side Story. It took me 4 tries to find the version I was looking for.
ETA: I just fixed all the old links I hope.