Storage can be a bit of an issue on the Switch; the console's internal capacity is only 32GB, with a portion already reserved for the operating system, and bigger micro SD cards can be very expensive. Thankfully, you can rely several of the smaller, more affordable cards with relative ease. For those of you getting to the point where your initial storage is filling up, and as an alternative to the 'Archive' option on the system, below is the step-by-step guide for keeping multiple cards on the go.
First of all, power off your console by holding the power button until the Power Options menu appears, and select 'Power Off'. Do not just put your console into sleep mode, or you run the risk of causing irreversible data corruption.
Once your console is off, simply flip it over and lift the kickstand up to reveal the micro SD card within. Take it out and replace it with your new card and re-close the kickstand.
As far as the process goes, you're basically done. The only thing to bear in mind is that of course none of the games from your other micro SD card will be present, but their icons will be accompanied by a little cloud icon.
To play any of the games you've purchased simply press the A button to download them onto this new card and start gaming to your heart's content. Because all your save data is stored on the console's internal storage it'll still be there ready for you to use so you can dive right back into your games.
Of course, this can also be applied to new games you purchase from the eShop, allowing you to flip between SD cards depending on what games you want to play and when. This process becomes especially helpful when downloading larger games such as The Legend of Zelda: Breath of the Wild.
Just make sure you keep the little sods in a safe place.