Mercurial is a free Tumblr theme that comes with an Instagram-inspired layout. This theme allows you to choose from 7 post sizes, ranging from 250px to 540px. Thi theme also comes with a popup where you can include your CTA texts, update areas, link to one of your pages, etc. This theme even comes with the like & reblog buttons, which look just like that of Instagram. This theme also comes with the option to show or hide the options and even, to shorten the long ones. With this theme, you can also insert an optional dropdown menu with the blog’s pages. This theme comes with a highly elegant timeline-styled layout, which makes it one of the most beautiful themes in our collection.