XFractLab is described as 'Program to render fractals using specialized formulas. Built in compiler lets you image a wide variety of fractals while maintaining high performance. Multithreaded renderer scales with any number of cores, allowing to use your machine to its full capabilities' and is an app. There are more than 10 alternatives to XFractLab for a variety of platforms, including Windows, Linux, Web-based, Android and iPhone apps. The best XFractLab alternative is ExploreFractals, which is both free and Open Source. Other great apps like XFractLab are Xaos, Sterling2, Ultra Fractal and Apophysis.