Most of my earworms these days are the songs I hear repeatedly on anime.
First up is from JoJo’s Bizarre Adventure. While I was aware of Yes, I'm not sure if I could have ID'ed them blindly. Every episode I heard this song Roundabout. At first I didn't know who had done it and assumed it was a current song. It started to just play in the back of my head every day. Eventually I paid attention to the credits and had an Ah Ha! moment. I ended up listen through their discography on Spotify. Good stuff.
There were 4 endings in total and this video splices them all together for the full song.
JoJo’s Bizarre Adventure Ending PROPER Full