Reddit reviews BCW Protective Pages Crystal Clear for Photographs or Postcards | 2-Pocket Page | Pocket Size 5 ½" x 7 ⅛" | (50 Page Total)

for large creatures!

The hole punches are pretty cheap on amazon ($11 for 1", and $12.50 for 2"), so even if you only deal with a few dozen large creatures over your DM life, it could still save you a decent chunk of time. But I'd totally understand if it's not a regular thing for you/your campaign(s).

For me, because I play on a whiteboard on the wall instead of on a mat on the tabletop, I instead use 2" per 5ft so that my players can more easily see everything.

I also print a lot of doubles for each token in different colours. This means that each mini has a unique colour (or different hair, weapons, etc). Which gives me flexibility to represent different setups for a fight, and it helps me keep track of each creature's hp without having numbers on every single mini.

To store and organise all of them, I bought some 3-ring binders, and clear photo sleeves. I also "borrowed" a sheet of sticky labels from work.
Originally I just used one envelope per monster type, and rubber-banded them together. But I found that got really annoying to deal with once I got to like 15 different monsters - an alphabetised folder is much faster and easier to flip through.

I don't know if they'd fit all or even some of your cards but maybe one of those big sturdy photo albums would work? Might be easier to find in stores too.

Otherwise they sell these on amazon and you could find a 3 ring binder that you like to go with them.

I actually need to find a way to keep mine stored too, mine are all on my desk or in a shoebox with my mailing supplies.