mountbatt

This plugin adds a separator between the intro text and the extended (more…) text of the content of a post. It simply replaces the span id more tag with the separator that is set in the plugins php file.
Some separator samples are given there.
Upload into the /plugins directory and activate it in the Plugins Menu.
History:
1.1:
Fixed a bug that forced WordPress Adminmenu to show a white blank page.
1.0:
Initial Release

Add a Separator

Simple Plugin to add a separator between the intro and the (more...) content.

ramon fincken

Auto sets the more tag to post title if no custom text has been set. 
 Auto text is customizable using mp_auto_more_more_link_readmore filter in the Premium version: 
<a href="https://webshop.mijnpress.nl/shop/wordpress-auto-more-tag-text" rel="nofollow ugc">Buy premium</a>
Coding by: <a href="https://www.mijnpress.nl" rel="nofollow ugc">MijnPress.nl</a> <a href="https://twitter.com/#!/ramonfincken" rel="nofollow ugc">Twitter profile</a> <a href="https://profiles.wordpress.org/ramon-fincken/" rel="nofollow ugc">More plugins</a>

MP Auto more tag

Auto sets the more tag to post title if no custom text has been set.

Add a Separator vs MP Auto more tag