I'm having trouble correlating relay schematic component symbols with pcb layout patterns. The component list is extensive with (somewhat) standard patterns. Is there some index that matches the pattern to a particular relay by dimension? Is there any general way to identify component symbols matched with patterns?

Ideally, I would like to select a PCB footprint and see all schematic symbols that are associated with it. I saw no obvious way of doing this. Is it possible?

You can open a library in Component editor, select "Component/ Search in Libraries", type pattern name in corresponding field and press Find now button. In few seconds, all components with specified pattern will be found.

I anticipate basic conception is one of the best analytical elements in an PCB Layout package, because best of the time you accept to, or demand to body your own apparatus aloof the way you adopt them.
If basic conception is over complicated and unintuitive than that's IMHO a absolute accord breaker for a pcb package.
As you showed in Diptrace it is actual accessible to actualize apparatus in allegory to added programs.