If you're looking for a good portable monitor to pair with your 12.9" iPad Pro, here are a few solid options to consider:

1. Asus ZenScreen MB16AC (15.6", 1080p)

• USB-C connectivity, perfect for iPad Pro
• Slim and lightweight at only 1.7 lbs
• Smart cover doubles as a stand
• Built-in battery provides up to 4 hrs of use

2. Lenovo ThinkVision M14 (14", 1080p)

• Two USB-C ports to connect to iPad Pro and charge devices
• Ultra-thin at 0.17" and only 1.26 lbs
• Adjustable stand with tilt from -5° to 90°
• Protective sleeve included

3. Lepow Z1-Gamut (15.6", 1080p)

• USB-C port for connecting to iPad Pro
• Slim profile at 0.3" and weighs 1.7 lbs
• Includes smart cover and screen protector
• HDR mode and dual speakers for entertainment

4. Espresso Display (13.3" or 15.6", Touch, 1080p)

• Designed for creatives with touch and pen support
• USB-C connectivity
• Magnetic mounting system
• Includes protective case

When choosing a portable monitor for your iPad Pro, prioritize models with USB-C connectivity for easy plug-and-play functionality. Also consider the screen size, resolution, portability, and any included accessories like cases and stands.

I personally recommend the Lenovo ThinkVision M14 for its ultra-slim design, dual USB-C ports, and adjustable stand. But any of the monitors listed above would make an excellent companion to expand your iPad Pro's screen real estate on the go.

• ASUS ZenScreen MB16AC 15.6" Full HD IPS USB Type-C Portable Monitor
• Lenovo ThinkVision M14 14" Full HD IPS USB Type-C Portable Monitor
• AOC I1601FWUX 15.6" IPS Full HD USB Type-C Portable Monitor These monitors connect directly to the iPad Pro via USB-C and provide a secondary display for expanded productivity.

UPERFECT True 4K Portable Monitor, I use this, works as promising.