The AVH Extended Categories Widgets gives you three widgets for displaying categories.
The plugin doesn't work at all for me. Uncatogized is the thing that pops up though I have posts in other categories they don't show up.
I'm just going to delete and find one that works and has screenshots that show how to set it up and what it looks like when its set up.
Its 2013, i think this is far too complicated for what it is.