Basemark's latest mobile gaming and graphics benchmark is Basemark GPU Mobile (Android, iOS), which really puts the screws to your device, testing support for OpenGL ES 3.1 and Apple Metal. The app runs through a highly detailed scene designed to push your smartphone or tablet to the limit (single digit FPS at highest settings are not uncommon). The scene features a variety of lighting effects, SSAO, particle effects and post-processing. The free consumer version doesn't let you tweak the benchmark settings much, and simply runs the benchmark, provides you scored results, as well as a link for comparing your device's results online. A premium version ($5.99).