I use the Wayback machine sometimes.

Norm MacDonald’s old youtube podcast is on there, while it’s hard to find anywhere else (they took it down from youtube when he got his Netflix show).

I’ve found public domain pictures on there, and I’ve spent time browsing very old music.

I went down a rabbithole of comparing evolving definitions of words by reading through generations of dictionaries. That would be hard to do without the IA. As well as comparing versions of books that I was considering buying.