First off, thank you for Affinity Designer's powerful toolset. It's a joy to use!
When I am using Affinity Designer to create complicated presentations with multiple artboards and nested groupings, I wish for 3 key tools to make my job faster, easier, and more controlled. Tools that obliterate tedious tasks can mean the difference between enjoyable and monotonous, between making money and losing money as a designer. Let me know if you think these three suggestions should be added to Aff
This is how I could see tags working:
Add a "Layer Tags" panel. Layer tags are named, in a flat namespace (no hierarchy needed), and global to the entire document (independent of spread or artboard).
Any given layer can have one or more tags associated with it. A layer which has one or more tags associated with it would show a tag icon in the Layers panel, and the tag icon would be a different color when that tag is selected in the Layer Tags panel, to help identify which layers are