What are list pets?

[Pathetic_aesthetic_]

Hi! I’m not new but I’ve never understood what list pets are? Could someone please explain and tell me which are? Or at least please send me a link to some forum explaining? Thank you!

[Pyromaniacal]

"List pets" are the rarest pets on CS. While the list is user-created and unofficial, it has become a universal guide for almost every active trader on the site. For more information, see the Rares List Guide.