There is still a lot of people using a facebook for they "main" socialmedia. a lot of people have facebook app on they smartphone, but lately Facebook aps consume a lot of ram, it can cause slow down to our smartphone.
if you still want to use it, you can make internet shortvut from your browser so you could save some ram from your smartphone.
2. Weather Application
Yes sometime we need to know about weather that possibly could happend. but if you just google it you will save some ram "space" on your phone. and maybe you can make a shortcut in your mobile browser too.
3. Free Anti-Virus
We should use our phone wise, instead we using or downloading free anti-virus we should use our smartphone wisely, Android claim they system already secured from major encryption.
4. Cleaner Aplication
This kind of apps promise us to "clean" any file from our uninstaled aplication, but sometime they still left some chace, to clean it you can go to "settings" - "apps" - "downloaded" then you can shoose your application and then shoose "Clear Chace"
5. Default Browser
There is a lot of browser that you can use instead your default browser, you can use opera mini, chrome or anyting else.