To look for more courses, tap the + icon in the top right corner of your course selector (pictured). Or the 'Find' tab from the main dashboard.
Tap ‘Or browse more courses' for more courses under that language.
Tapping 'Other topics' will show you more non-languages topics such as science, history or hobby related courses.
For a more exhaustive course search please consult the website. Once you start learning a course in the website, it will automatically sync with your app, provided it is connected to the internet and logged in with the same credentials. If your mother tongue is not English, you can change your native language in 'Edit My Profile'. To do so follow these instructions. You'll then be able to see any community and Memrise courses created in your native language.