Phones are nicer to use without cases, but not for long if you tend to drop things. MNML's offerings are slimmer than just about any other case, and preserve a semblance of that caseless feel while providing more protection than a skin. You can grab one for a Pixel 3 or 3 XL for 10 bucks right now, $5 less than the usual price.
Now, these aren't cases that'll save your phone from a catastrophic five-foot drop onto pavement; at less than half a millimeter thick, they're more insurance against scratches and dings. You can pick from blue, red, matte black, frosted black, and frosted white colors (although the white is more or less clear).
Opinions on the cases are pretty divided, but if you know what you're getting into (minimal protection with minimal bulk — get it? MNML?), they're an interesting option. Swing by Amazon to pick one up — the normal and XL sizes are the same price.