Dutch van Andel

This simple plugin is a must-have for anyone that works with custom taxonomies or post types – and is an especially good compliment 
to Brad Williams’ indispensable <a href="https://wordpress.org/extend/plugins/custom-post-type-ui/" title="Custom Post Type UI" rel="ugc">Custom Post Type UI</a> plugin.
By default, WordPress only shows built-in taxonomies in your administrative list tables (e.g. Categories & Tags). But 
if you rely on custom taxonomies for organization (particularly when working with custom post types) then you are 
typically out of luck.
This plugin fixes that – ensuring that custom taxonomies are added as columns to all necessary list tables automatically.
This is an initial release and includes no bells or whistles – but if you need this functionality, you’re likely a developer 
just looking for a good head start, anyway. If you have any improvements, additions, or suggestions, please leave a post in the 
WordPress.org forums with the correct <code>custom-taxonomy-columns</code> tag.

Custom Taxonomy Columns

Automatically adds custom taxonomy columns to admin list tables.

littlejon

LJ Multi Column Archive is a WordPress plugin/widget that allows you to display your archive list with multiple columns.
I developed this plugin as I wanted to make use of the space I had in the sidebar more effectively, while still keeping the links to all the archives available.
Depending on how old you blog is you can set the Archives to display either a list of Months with Posts, a list of Years with Posts, or a list of Days with posts.
Archive links can be shown with or without post counts.

LJ Multi Column Archive

LJ Multi Column Archive is a Wordpress plugin/widget that allows you to display your archive list with multiple columns.

Custom Taxonomy Columns vs LJ Multi Column Archive