I'll just list the not-so-common ones, as of 9th July 2015:
iOS:
Citymapper - initially not so useful, but now, it has improved dramatically, though it's very city-specific. Good for travelling and sometimes useful for travelling in Singapore too.
Accuweather - the Real Feel feature is pretty accurate. That's all I use from this app.
You know, stuff that you find indispensable, use very often, or are delightful.