In SAP Fiori Launchpad user can personalize it and select their theme of choice as well.
This blog discusses the way to find all the users who has adapted the page layout e.g. adding tiles to user home group or managing tiles for other groups that allow user personalization.
UI-SAPUI5-Fiori
Find the Users with personalized Theme selection in Fiori Launchpad
In SAP Fiori Launchpad user can personalize it and select their theme of choice as well.
This blog discusses the way to find all the users who are not using the default configured theme and has their own choice of theme in the Fiori Launchpad.
Design
Create a prototype using SAP Build
Consumption View (CDS)
Create CDS view which can be consumed by OData and subsequently by User Interface
User Interface Development
Develop User Interface by consuming Annotation based OData service via FPM or Fiori Elements