Mega Sales Lite extension allows you to set special prices for entire product categories, manufacturers, products with specific filters, and for their combinations (category and manufacturer and filter combinations).
Extension is built with compatibility in mind – to have a good looking OpenCart theme that would work with most of the OpenCart extensions without any customization or compatibility issues, and to have an ability to upgrade OpenCart versions without a headache.
Responsive Facebook Page Plugin lets you add Facebook Page Plugin (ex. responsive Facebook Likebox) to your OpenCart store. It reloads and adjusts itself if screen size changes so works nicely with responsive layout stores.
Much improved OpenCart store sitemap for Google, Bing and other search engines: works much faster than the default, dynamically generated OpenCart sitemap, excludes disabled products, works with custom image titles, can be executed manually (link in /admin), or set up as cronjob.