To figure out how to actually search for specific types of objects, use Edit > XML Editor. (or open the SVG in a text editor)
Hopefully these shortcuts help though:
text | id="text" |
rectangles | id="rect" |
objects with the same color | see here |
lines | Inkscape doesn't distinguish between "lines" and "shapes". They are both considered "paths". I often use style="fill:none", but that will also pick up unfilled shapes too, if they exist. |
dashed lines |
style="dasharray:" selects all lines,
and style="dasharray:none" selects UN-dashed lines, so move the first to a temporary layer, and then move the second back to the original layer |