Expanding Archives adds a widget that shows your old posts in an expandable/collapsible format. Each post is categorized under its year and month, so you can expand all the posts in a given month and year. This plugin comes with very minimal CSS styling so you can easily customize it to match your design. Expanding Archives uses Font Awesome icons in a few places, so having that installed is recommended. However, the widget still functions perfectly fine without them. JavaScript is required.
