Adds a widget to list or reference fields that let's you select "other" and provide a value.
See also: Select Text Value
Issues to watch:
Provide option to not save value
https://www.drupal.org/project/select_or_other/issues/2694251
Text fields not working
https://www.drupal.org/project/select_or_other/issues/2822516
Module page
Stability
Alpha