I would like to find a monitor of about 15" size as a companion to my macbook pro edit system. i need a compact size for space management and travel. Seems better quality monitors are all over 20".
Suggestions?

What resolution, Ed? HD? 4K?

Ed, do you have an iPad? Duet is a pretty cool app that will minor or extend your desktop onto the tablet for about $20.

I have an Ipad Air which is pretty small plus it is pretty low rez, so I dont think that will suffice. A large tablet is still only a 9" screen.

I would much prefer a minimum of 1920 X 1080. 4K would be nice but not necessary. There are some interesting options like: ASUS MB169C+ 15.6" 16:9 Portable IPS USB-Powered Monitor. Not sure how well this type of device would perform for color correcting. 700:1 contrast ratio. But as of now I am only using the macbook pro 15 (newest version) screen for editing.

My counterpart at trial I think is using chic

https://www.wiknix.com/best-portable-monitor-for-laptop/

Reading reviews of the ASUS monitor I found this comment:

"Monitor will not play back at full frame rate uncompressed video in any video player. If you are using Adobe Premiere CC this monitor will be useless to you. You cannot preview footage from Adobe on this monitor, let alone use it as your main monitor for editing. I don't think USB 3 is ready for secondary monitor at this time as their is not enough VRAM to run uncompressed footage through the USB port."

Not good!