There are so many books/series that I've re-read over the years that I don't think I'll be able to come up with even a fraction of a list.

Like most of us in the past 25 or so years, I'll add the Potter books - I'd re-read them while waiting for a new book to ship (first one I had to wait for was Goblet of Fire) ... and have likely re-read them 10 or more times, not counting reading them aloud to my now-12-year-old. (Dialect spelling, though ... *wipes sweat from brow knowing I've mangled it for Yorkshire and its surrounds*)

As a kid, I stopped visiting the library because I struggled to find interesting and LONG books ... and waiting for an inter-library loan was really hard, especially if I had no way to get there & pick it up in time. (I'd walked a few times, but it was literally several miles and, non-hyperbolically, uphill both ways ... not to mention the streets being narrow & not at all conducive to walking safely.) So, my options were ... raid Dad's books or re-read my own. I did both, often swiping copies from Dad (which I still have 30-odd years later) or having to Scotch-tape tattered and well-read paperbacks together so I wouldn't lose pages.

Dracula is a frequent re-read, and I find new details every time I read.

The Scarlet Pimpernel was one of my favorites in middle school; I'd switch off between it and A Tale of Two Cities for re-reads until I "discovered" the Vampire Chronicles. (Actually, it's less "discovered" and more "Dad didn't have anybody else to talk to about books, so he pulled a version of 'Neil Gaiman talking to his daughter about Goosebumps' when I was reading Dracula ... fortunately, it turned out better for me than for Gaiman's daughter. Well, mostly. I wasn't scared by the books, but I probably should've been reading other things!)