Archive.org if you are looking for a public place.

If you are looking for private use, I would recommend taking a small/old PC and run Yunohost with Nextcloud.

Also all depend on the stuff you’re talking about…

Why someone would storage something forever WO getting something back?

Storage power isn’t free…

Create a torrent, it will stay up as long as someone keeps seeding it.

If you’re tech-savvy, or willing to learn, A nextcloud instance would be my goto