Stackables is a pretty cool phone app that provides layer-based way to create awesome photo effects. At present, its iPad version is available for free.
Apparently compared with its iPhone version, Stackables for iPad sports a larger operation interface plus reasonable layout in order to bring you a more comfortable way to enhance your photos. The phone app comes with more than 150 photo effects and variations, and features an advanced and comprehensive layer-based adjustment. This means you can freely add layers with different photos effects to your photo, and every layer can be modified, so you can create numerous one-of-a-kind effects, and formula feature lets you save your modification processes for quick access or share your formulas with friends via Email, moreover, the photo app has 30 preset formulas, and over 20 professional adjustment tools allow you to adjust your photos detailedly. Apart from that, Stackables for iPad supports 3000 x 3000 and 4000 x 4000 resolution, and PNG format, and sharing via social media such as Facebook, Instagram, Twitter and etc.
Stackables for iPad is available for free at present. If you need the iPad app, head to App Store for more details.