By default, WordPress only display the author and plugin URI links. Since the version 2.8, they applied filter plugin_row_meta within the plugin administration section. With this filter, you can create many links for your plugin or another plain text.

You can see the filter changes log below:
2.8 wp-admin/plugins.php
2.9 wp-admin/plugins.php
3.0 wp-admin/plugins.php
3.1 wp-admin/includes/class-wp-plugins-list-table.php
3.2 wp-admin/includes/class-wp-plugins-list-table.php
3.3 wp-admin/includes/class-wp-plugins-list-table.php

Let’s start to create the additional links by using the filter. First, create function that returns the links in an array and then add the filter with your function.

Put this function in your main .php plugin file:

function my_plugin_links($links, $file) {
	$plugin = plugin_basename(__FILE__);

	if ($file == $plugin) // only for this plugin
		return array_merge( $links,
			array( sprintf( '%s', $plugin, __('Settings') ) ),
			array( '' . __('Link 1') . '' ),
			array( '' . __('Link 2') . '' ),
			array( '' . __('Link 3') . '' )
		);
	return $links;
}

add_filter( 'plugin_row_meta', 'my_plugin_links', 10, 2 );