hopstep

This ‘Display Post Number’ is a plugin that you can set the number of articles to be displayed in the dashboard. 
It is a plugin to support only Japanese.

Display Post Number

This 'Display Post Number' is a plugin that you can set the number of articles to be displayed in the dashboard.

Chip Bennett

This plugin will allow you to customize the number of posts, orderby, and order parameters for all index page contexts, including the blog posts index, search index, and all archive indexes (category, tag, taxonomy, author, date, archive). Orderby settings support all values relevant to archive index pages, including none, ID, author, title, name, date, modified, rand, and comment_count. Order settings support ASC and DESC.
Note: Plugin settings can be configured via Dashboard -> Settings -> Reading.

cbnet Different Posts Per Page

Customize the number of posts, orderby, and order parameters for all index pages (blog/home, search, category, tag, taxonomy, author, date, and archiv …

Display Post Number vs cbnet Different Posts Per Page