Hi
i would like to use some card configuration (vertical/horizontal stacks for example) over multiple tabs since every family member has its own tabs. a lot of elements are just copy paste on those tabs. Its quite a pain to keep all of them in sync when i am editing something. it would be awesome if it could be possible to just reference a card “template” which is editable at one point and viewable on multiple dashboards.
That would really make my life easyer! 
With 5 users in the house, each having their own dashboard, but sharing 30% of the cards on all dashboards. Makes updating an pain in the a**…
Managed to scale things down by setting buttons to navigate to invisible “subviews”.
But it does’nt really acomplish what i’m looking for.
This option could also scale down the yaml file and free up some RAM an cpu.
It’s not just sharing across multiple users. I have a large number of mini-graph-card charts that all use the same yaml snippet to plot a shading for day/night. I’d love to be able to “!include” these as I do with yaml-based dashboards. I’d be more than happy to have HA let me do it but say “Visual editor not supported” (especially since mini-graph-card doesn’t currently have a UI editor anyway).