kegentile

This plugin will create a tag cloud for a specific author. This will allow a visitor on your site to drill deep down into an author’s specific content.
It uses all of the same parameters as wp_tag_cloud(), but adds an additional one for the author_id. When the author_id is passed an integer of a published author that has tagged his or her posts, a tag cloud will be generated.
It will also create a new permalink structure on your site of
www.yoursite.com/author/author-slug/tag/tag-slug
***Note: that you must be using any custom permalink structure for this plugin to function. Also, custom taxonomies is currently not functioning with this version, please look forward for this in a later version.

Author Tag Cloud

Creates a template tag to create an author specific tag cloud and creates a new permalink structure to drill down into content by author and tag.

The Krotek

Customizable widget and shortcode to display tag cloud anywhere you want. You can use it as standard tag cloud widget, as shortcode in any post or page, or both ways. Tons of options allow you to fine tune cloud layout to your needs.
STANDARD FEATURES
<ul>
<li>Display list of post, category or link category tags.</li>
<li>Define number of tags to be displayed.</li>
<li>Set custom tag separator.</li>
<li>Select tag taxonomy: posts, categories or link categories.</li>
<li>Choose cloud mode: shortcode only, widget only or both.</li>
</ul>
PREMIUM FEATURES
<ul>
<li>Define smallest and largest tag size.</li>
<li>Select size unit: px, pt, em or percent.</li>
<li>Choose layout: standard flat cloud or unordered list.</li>
<li>Order tags by name or count.</li>
<li>Sort tags ascending, descending or randomize.</li>
<li>Define list of tags to exclude from cloud or include only.</li>
</ul>
You can purchase Premium version <a href="https://thekrotek.com/wordpress-extensions/tag-cloud" rel="nofollow ugc">here</a>.

Custom Tag Cloud

...but it at least is a little better than the one that comes with WordPress.

Free version is not very customizable...

Customizable widget and shortcode to display tag cloud anywhere you want.

Author Tag Cloud vs Custom Tag Cloud