For portable humidifiers for space themed desk setups, useful comparison points include placement, dimensions, power method, capacity, controls and the specific functions represented by the search.
Catalog options relevant to this combination include USB Mini Desk Humidifier, Compact Portable Car Humidifier and Relaxing Aromatherapy Essential Oil Diffuser, and Compact USB Mini Air Humidifier. Their exact specifications can differ, so use the individual listings for final product details.