The first thing I bought for myself was a traveling bag big enough to fit the charger in as well. It came with two cases that can carry 12 games and it's really all I need, you can't really toss the Switch in your bag like you could with a DS or any other old handheld console.
If you play handheld at all, I would really recommend the Satisfye joycon grip. It makes holding it so much more comfortable. Doesn't damage/scuff your Joycons or Switch at all either. I love it. Also a glass screen protector would be good, the dock can scuff the screen if you're not careful putting it in. Learned that the hard way before I got my screen protector :'(
Thank you for all of your help everyone! I'm planning on getting a NH theme case when those release, the charger stand, and a screen protector. Will also get an SD card to make sure I have room for games.
If you play handheld at all, I would really recommend the Satisfye joycon grip. It makes holding it so much more comfortable. Doesn't damage/scuff your Joycons or Switch at all either. I love it. Also a glass screen protector would be good, the dock can scuff the screen if you're not careful putting it in. Learned that the hard way before I got my screen protector :'(