I use this New 2DS XL Case which obviously also fits 3DS XL/New 3DS XL. It’s like $10.

There’s ~1 inch of extra vertical space so I’d expect it to get jostled around a bit if I ever intended to carry this around (I only play video games at home). Still, it’s a hard case with a soft felt interior so I wouldn’t be worried about any scratches or damage to the Analogue Pocket. It should absorb impact against most normal drops.