Back when it first came out I used to play A LOT of C&C: Tiberian Sun online for years. Shoutout to my ally "Minibar" if you're still around and kicking!
Anyway, I've started playing C&C games in multiplayer again and found all the original 2000-2001 maps you'd automatically download when playing with/against others in online matches...
...there's 123 of them!! I have no idea if you diehard C&C fans consider these multiplayer maps classics, but they are all I know, so I figured we should preserve them online. I've zipped them up and together they fall just below the 1.5MB file attach limit on these forums, lucky!
I do believe you can simply drop these map files into your main install folder and they'll show up for you to select/share when starting online games.
Enjoy! And please do share your own.