[phpthrowaway99]

There are countless self publishing companies, and while idk if it's still active, even Amazon had a try at this.

[eslaught]

Yes, Amazon still runs theirs. It's part of the KDP program now.

lulu.com is another relatively big one. (They have a nice service, Lulu Xpress, if you just want to print copies for personal use.)

And then there is the other monolith, IngramSpark.