These are like ziplock but sturdier.
JARLINK 18 Pack 8 Sizes Zipper Mesh Pouch, Waterproof Zipper File Bags Document Pouch Multipurpose Travel Bags for Office Supplies Cosmetics Travel Accessories https://smile.amazon.com/dp/B07VBF4CYK/ref=cm_sw_r_cp_api_glt_fabc_JF00MJGX9G37WM9TKQ1Z?_encoding=UTF8&psc=1
I stitch on the train most days. I keep organized with mesh zipper bags similar to these. I use the large size for paper patterns and my cloth, and put in use bobbins and accessories in smaller ones inside. It keeps everything together and reasonably protected even though it’s just shoved in my backpack. Also more durable than the ziploc style bags I used before.
We use an MZ Wallace backpack and have been very happy with it. Fits a ton, super lightweight, can run it through the washer, and it’s a neutral color so my husband doesn’t feel ridiculous carrying it. We use lots of pouches to keep things organized - these Amazon ones are our current favorites: https://www.amazon.com/JARLINK-Waterproof-Multipurpose-Cosmetics-Accessories/dp/B07VBF4CYK
We also used Como Tomo bottles and I usually just packed a separate small insulated lunch bag with her bottles - though, I was also often able to fit that inside the backpack too!
I see you like organizing! I use these things for inside of my game boxes to organize pieces:
JARLINK 18 Pack 8 Sizes Zipper Mesh Pouch, Waterproof Zipper File Bags Document Pouch Multipurpose Travel Bags for Office Supplies Cosmetics Travel Accessories Random color https://www.amazon.ca/dp/B07VBF4CYK/ref=cm_sw_r_apan_glt_i_N8V2HCHX96S5MRVC76R3
Idk if that link will work...
I always stock up when I visit DAISO (basically the Japanese Five Below), but most people don’t have access to one. Here’s a multi-pack from Amazon: https://www.amazon.com/dp/B07VBF4CYK/ref=cm_sw_r_cp_api_i_gVfJFb9ZZ7RPN
They also have packs of just the big sizes, if that’s what you’re looking for. I can’t recommend these bags enough.
JARLINK 18 Pack 8 Sizes Zipper... https://www.amazon.com/dp/B07VBF4CYK?ref=ppx_pop_mob_ap_share
Was it these? I bought two packs and organized all puzzles and a couple travel games in them. Seriously useful stuff!