I would like a way to limit selection to certain object types so I suggest something like this:
When a tool (line, text, etc.) is selected, holding Shift and clicking selects objects that are of the type produced by the tool, and Ctrl-A selects all objects of the type on the page.
It would make it easier to make changes to, for instance, all text on a page at once, especially as LayOut doesn’t have named object styles (that might be another FR)