Limited set of allowed colors - Email Templates

In a custom email template, it would be handy to have a limited set of values for the "mktoColor" variable (represented by a drop-down list of a palette). 

Most brand guidelines only allow for a certain set of colors to be used. Currently, each person in charge of emails has to either look these colors up every time they build an email, or remember the hex color codes. Both of those are becoming not very practical as the volume of work grows, new team members get hired, or the guidelines change. Having a limited palette would not only save teams time and effort, but also guarantee against accidental use of off-brand colors.

Attaching an example from another app.