Gramatica is an Instagram client for the iPhone and iPad that lets you hide and filter unwanted photos. You can create lists of tags and people, or you can simply hide a photo that you come across in your stream. Gramatica also supports multiple accounts, pinch to zoom, and more.
Gramatica features a dark-themed social stream with all photos shared by your friends, but different from the official Instagram app, Gramatica reveals additional columns when you swipe left or right. Swiping to the right slides open a toolbar on the left with more tabs and options. Swiping to the left reveals your stream in thumbnail view so that you can quickly see 18 photos at a glance (on the iPhone 5).
With each photo on the stream, the username, avatar, and location associated with it appear just below. Tapping the avatar or user name will open the user's profile, and tapping the location slides open a little map in place of the photo. Similarly, tapping on the comment bubble or heart will slide in all the comments/likes with the ability to add your own. When adding a comment, tap a previous comment to tag that user. Double-tapping a photo will mark it as a favorite.
One of the unique and main features of Gramatica is the ability to hide photos and filter specific people and tags. You can also create lists of people and tags to add to your left sidebar for quick access. When viewing a user's profile, you can choose to hide or block the user or add them to a list you created. If you come across a photo in your timeline that you'd rather never see again, holding your finger down on it will reveal options to hide photo or user.
I seriously love Gramatica. The interface is beautiful, I get to hide the occasional ugly photo, and best of all, it's available on the iPad!