1. A method for populating a customized library comprising a plurality of selected pattern templates, comprising: displaying a plurality of renderings of sample content in accordance with at least one markup language element, wherein each respective rendering of sample content corresponds to a master pattern template of a plurality of master pattern templates, the respective rendering of sample content comprising a rendering of at least one markup language element, and the plurality of renderings of sample content visually represents a master pattern template library consisting of the plurality of master pattern templates; detecting a selection of two or more of the plurality of renderings of sample content that corresponds to a subset of the master pattern templates of the master pattern template library; displaying an indication of whether a respective master pattern template is compatible with a plurality of output formats; populating a customized pattern template library based on the selection; and displaying a representation of each pattern template of the customized pattern template library in connection with a user interface of a content editing tool.