I associate amber monitors with three things:

* DEC terminals at my school, all our grades and stuff lived in a VAX and the office personnel accessed it through VT220s or maybe VT320s

* the InfoTrac at the public library, late 80s early 90s. This was a search engine for newspaper and magazine articles that you could find in the microfiche section of the library. It basically consisted of a PC -- maybe XT or AT class with the entire search database on wonderful new things known as CD-ROMs. Text mode only, the amber monochrome monitor was hella stupid burned-in.

* one time my dad set up a Northgate 386 for his company with Xenix on it and it had an amber monochrome monitor.