If you are interested in more examples on what virus payloads did on activation, danooct1 on YouTube has recorded lots of them (link goes to the MS-DOS playlist): https://www.youtube.com/playlist?list=PLi_KYBWS_E71ObQ8QpGj5...
Wish I knew the most interesting/popular of these.
My first virus/worm(one that wasnt adware from freeware games) was the Conficker-
https://en.wikipedia.org/wiki/Conficker
Think I got it for sticking my USB in college and HS computers. Back then having a USB full of cool things was a big deal. I probably infected hundreds of computers.