Apple’s Dashboard was a cool feature that somehow missed the mark at least for me. Maybe it is that it’s in that hidden view and it would be more useful if you could always see the widget. Don’t know. But basically, I never got much use out of Dashboard.
If you did, you’ll have to either make a new widget yourself or hope that someone else did. Since Dashboard widgets only work in Dashboard, there’s no hope that you can use the actual widgets you’re used to in something else.
Honestly I haven't tried to replace it since I wasn't using it but these may be options if you want something similar.