Back in 2019 I made a post discussing my solution for storing wax packs. Like many of you, I'm using a toploader as a backer and putting them in a bag - a team set bag for 3x4s and a graded card sleeve for the 3x5s (it's a little too wide but close enough). See below:
I recently investigated bags for my 4x6 toploaders that I use for oversized packs and found one on amazon that works well from a company called Golden State Art. They run about 8 cents a bag.
Click the picture below for the link: Amazon links keep changing so I posted the current ad below that.