https://www.amazon.com/gp/aw/d/B082YKRGL5?psc=1&ref=ppx_pop_mob_b_asin_image

Pricey, but worth!

My wife got me this really nice backpack for carrying my more competitive decks around. I have a dual-mat tube strapped to the side and I keep stuff like the Planeschase deck and dry-erase tokens in the front pouches. It's quite handy.

https://www.amazon.com/ENHANCE-Backpack-Playing-Card-Case/dp/B082YKRGL5?ref_=ast_sto_dp

Before this, I had an old original Xbox tote bag that carried just as many decks, but little else. I still use it for my more casual decks.