https://www.levenger.com/products/vintage-library-catalog-cards-set-of-50?variant=43444256243861

These don't have the pre-drilled holes, but at least are still offered, though at the price gouging cost of $14.50 for 50 (in 2024).

Cost per card: $0.29

https://www.levenger.com/products/card-catalog-box?variant=43007544066197

A bit on the small side, but has a built in pen holder:

https://www.levenger.com/collections/pocket-briefcases/products/bomber-jacket-international-pocket-briefcase?variant=42485604778133#

Levenger sells a line of various "pocket briefcases" which include space for 3 x 5" index card "ticklers" which are similar in form to the old Memindex.

A 9 x 5" card that folds in three to make a 3 x 5" card for planning out one's entire week.

This is quite clever with respect the space of cards like Analog and 3x5 Life.

https://www.levenger.com/collections/notecards/products/perfect-timing-3-x-5-cards-90-cards?variant=42485738045589#

Slightly different than today/next/someday, Levenger sells 90 today/tomorrow/someday 3 x 5" index cards for $14.50 (or $10.00 on sale).

https://www.levenger.com/collections/pocket-briefcases/products/bomber-jacket-int-pkt-briefcase-w-pocketini-clip?variant=42636956237973

https://web.archive.org/web/20060309154747/http://www.levenger.com/PAGETEMPLATES/PRODUCT/Product.asp?Params=Category=17-722|PageID=4035|Level=2-3

https://web.archive.org/web/20050525173720/http://www.levenger.com/PAGETEMPLATES/NAVIGATION/PRDPREVIEW.ASP?Params=category=17-722|level=2-3|pageid=4209|CatID=17-722|Lvl=2-3|Special=featured

https://mleddy.blogspot.com/2005/05/tools-for-serious-readers.html

Interesting (now discontinued) reading list product from Levenger that in previous generations may have been covered by a commonplace book but was quickly replaced by digital social products (bookmark applications or things like Goodreads.com or LibraryThing.com).

Presently I keep a lot of this sort of data digitally myself using either/both: Calibre or Zotero.