David Powell

Retain Author allows you to force your “next” and “previous” blog posts to stay within the same category and the same author.

Retain Author

Prevent mixing authors in your next and previous post links.

Paul Ryan

Description: Widget that provides “Parent | Previous | Next” buttons to navigate between pages at the same hierarchy level (and up to the parent page). You can modify the settings to choose the words you want to use. To enable, first activate the plugin, then add the widget to a sidebar in the Widgets settings page.
View or contribute to the plugin source on github: <a href="https://github.com/uhm-coe/pager-widget" rel="nofollow ugc">https://github.com/uhm-coe/pager-widget</a>

Pager Widget

Prints "Parent | Previous | Next" links to navigate between pages at the same level in the page hierarchy (and up to the parent page).

Retain Author vs Pager Widget