In reply to Chris Aldrich.

Chris,

I ended up buying a field ammo box like this one (https://www.amazon.com/dp/B0CJDVBMCB?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1) that perfectly fits the index cards and provides insulation from moisture on top of it. It can hold around 1,000 cards and is very easy to lug around. Sometimes I feel like I'm going fishing with it ; )

For when I need more storage, I bought a Dewalt modular tool storage "suitcase" that also fits two rows of cards horizontally: https://www.homedepot.com/p/DEWALT-TOUGHSYSTEM-2-0-22-in-W-Small-Modular-Tool-Box-DWST08165/312134726

And for future proofing the above can fit on top of this double tool drawer system for even more cards: https://www.homedepot.com/p/DEWALT-Toughsystem-2-0-12-3-in-W-Tool-Box-3-Drawer-DWST08330/324196375 Currently I'm using it for various tools and notebook storage.

I got all these cheap on Black Friday specials last year FYI.

Hope this helps others and much appreciate your response.

Thanks!
Ray