Everybody talks about “Stairway to Heaven” being a ripoff of the Taurus song, which it obviously it. But the one that always got me was “Traveling Riverside Blues” by Robert Johnson. They didn’t even bother to change the name on that one, they just said “here’s ‘Traveling Riverside Blues’ by Led Zeppelin”. I don’t know how you pretend you wrote a song that existed for 30+ years and didn’t even bother to change the name of the song lol. And it’s not like Robert Johnson was obscure at that point, they had the big folk/blues revival of the 60s when Led Zep was starting out.
another big one is Kenny Wayne Sheppard’s “While We Cry”, which is a very blatant ripoff of Pearl Jam’s “Yellow Ledbetter”