This seller on ebay offers something like I think you are describing:
https://www.ebay.com/itm/A4-Cosmic-M...CA2E35m3sbYRiw
I can't say I have ever seen a vertical 3 pocket page in person.
Edit to add: From the description it appears that the vertical 3 pages are made for bookmarks if that is helpful in the search. There are a couple of other listings for vertical 3 pocket pages on ebay in which the columns seem too narrow for a baseball card, so make sure you know your dimensions I guess.