I'd find out many premium quality free Photo Gallery WordPress Themes with clean and simple style into a gallery layout for a showcase website designed by wpexplorer. in this list, the Pronto WordPress Theme is based the very popular jQuery Masonry, those free themes are licensed under the GPL license so you can use it for anything you want.

Jobpress is a very special wordpress theme from web2feel  to create a Job board based on wordpress.  With this theme you can host your own Job board website. Registered users can submit job listings on your site and an admin can review and publish it.

Krismas is beautiful wordpress theme released for the occasion of Christmas. This is a wordPress 3 ready theme with custom menu feature supporting menu descriptions, customizable message area on home page, widgetized sidebars and footer, theme options etc.

TechMatters is a Minimalist Magazine Theme that is aesthetically fresh and clean. This theme works perfectly using pixel perfect graphics and pictures to present the content. The theme is packed with outstanding features and options you can set in the admin panel. This Free WordPress Theme works in all major browsers, uses jQuery slider on Featured Articles, Thumbnails on Posts, Widget Ready, and more.

Ari is a minimalistic, flexible three-column blog theme. The theme uses CSS3 media queries for its responsive layout and is therefore optimized for tablet PCs and smart phones (the theme switches to a two-column layout when viewed on a horizontal iPad screen, and to a one-column layout on iPhones). You can also choose a dark color scheme.