Just about any app you can find in Play. Most of them are free, so install one that sounds good (read the reviews - that gives you a good idea if the app just doesn't work right), if you don't like it uninstall it, then install the next one. You should fine one you like better than the stock one. (I'm still looking for an email app by doing that. I haven';t really liked any of them yet - I got too used to Samsung's native email app.)