Looks like Amazon has the card boxes as well.

https://www.amazon.com/gp/product/B000K41E6K/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A1BLYNNJ3368EL

My card storage for an All-in pledge for campaign 1. Wanted to keep all the art work, but cut down (pun intended) on all the space the boxes took up. All cards, locations, and villain dashboards fit. I currently just have all the minis unpainted and jumbled in a mess in the stretch goal box until I finalize how I'll fit them all in there. I will also be 3d printing the token holder shared in this group, which should fit in this box with some slight rearranging of the cards. (https://www.etsy.com/shop/JSquaredDesignStudio)

I should also be able to fit the cardboard villain dashboards when I get those with my X-men All-in. My goal is to have all of each campaign in just 2 boxes. My only thing right now is trying to decide what to do with the gauntlet.

Box used: BCW Monster Storage Box, Holds 3,200 Standard Sized Trading Cards, 200 Pound Test Strength (1-Count) https://www.amazon.com/dp/B000K41E6K/ref=cm_sw_r_apan_glt_fabc_BGYCPPQZDEYRGTRTM0KV

Sleeves used: KMC Perfect Size Sleeves Topload Standard Size [10 Packs] USA Packaging https://www.amazon.com/dp/B08KYD29L8/ref=cm_sw_r_apan_glt_fabc_4AN2VKFY71W86BT2EHYB?_encoding=UTF8&psc=1

These were pricier, but I really like them. I will be using different ones for the second campaign to save some money

Sleeve Kings Card Game Card Sleeves (63.5x88mm) - 110 Pack, 60 Microns https://www.amazon.com/dp/B07RD9QZD2/ref=cm_sw_r_apan_glt_fabc_76YBGQ4N39NPSRAY15FK?_encoding=UTF8&psc=1

Dividers used: https://boardgamegeek.com/filepage/220250/horizontal-card-dividers

I taped a piece of index card to them to raise them above the cards, since they are actually the same height as the cards.

They start as small as like 200 or something and go out to thousands.

https://www.amazon.com/BCW-Monster-Storage-Holds-trading/dp/B000K41E6K/ref=zg_bs_2358923011_2

BCW Monster Storage Box, Holds... https://www.amazon.com/dp/B000K41E6K?ref=ppx_pop_mob_ap_share

If youre only going to temporarily put them in a box, go for a BCW box like this

Much cheaper than a plastic and fabric box, very sturdy, and is time tested to not damage your cards

https://www.amazon.com/BCW-Monster-Storage-Holds-trading/dp/B000K41E6K/ref=sr_1_5?crid=3I15FHPP05EPN&keywords=bulk+card+storage&qid=1646075212&sprefix=bulk+card+storage%2Caps%2C84&sr=8-5
I have seen people use boxes like this or similar to it.