I've wrestled with this over the years and settled on different heavy, nylon bags for each type/caliber. Think small to medium sized range bags, but I don't use ones with external pockets as I don't need them. These bags only hold mags, no ammo or anything else.
I may take 5-10 guns to range and by looking at bags, I know what ammo cans (caliber) to bring with me.
For example, one medium green bag is all .22LR. Open it up and there's dozens of .22 mags, whether it be 10/22, handgun, old marlin bolt gun, CMMG .22 mags for AR, etc. If it chambers .22LR, the mag goes in this bag. That's also where they are stored. Only time I remove them from the bag is at the range. At home, the bag is on a shelf in walk in closet.
Another bag is all AR mags. FDE mags are .223. Black is .30. Green is other (5.45X39). Since each caliber has its own color, I can tell at a glance what rifle or pistol they chamber with.
Another bag is all 9mm. If it chambers 9mm, mags are in this bag, including Glock and Springfield handgun mags as well as PCC mags for Scorpion, KP-9, Ruger PC Charger, AR-V, etc.
Small orange bag is Black powder stuff. This is only bag where I also include powder, projectiles, wads, caps, etc.
Yup, there's a bag for AK mags too. These are ONLY 7.62X39 mags.
Another bag is for oddball rifle mags such as 7.62X54 mags for SVT, VEPR and PSL. Hakim, M1A, M1 carbine and Mini 14 all go in this bag. There's probably a dozen or so Enblocs in that bag too.
Lastly, I have a small misc., bag for oddball handgun mags like .45 ACP, .40, 7.63 Mauser, etc. I know .45 may not be oddball to most, but I don't shoot it all that often. Same with .40. I only own one handgun in each of those calibers.
This works for me very well. I match bags to ammo cans. Of I don't need it, it stays at home. I have a big bag of drum mags for AR and AK's. It is very rare I ever shoot them, so that bag is stuffed in back of closet.