Here's the homescreen of my main Android phone (with some obvious apps omitted, e.g. Phone, Flashlight etc):

• Google Voice Search - I use it all the time for setting alarms and adding tasks to Wunderlist inbox.
• Google Fit - mostly for making sure I walk my 12000 steps every day.
• Opera - I use it instead of Chrome because it's the only browser that reflows text when zooming in.
• Wunderlist - an essential GTD app which I hate. I'm working on my own todo app to replace it.
• Barcode Scanner - to grab articles from the desktop PC to the phone via the QRCode Chrome addon.
• Google Docs - for work, use it all the time.
• Kindle - I read all my books via the Android Kindle app. I stopped byuing paper books years ago.
• Dropbox - I like to have all my files accessible to me at any moment.
• Trello - I use it a lot, for work projects, hobby projects, self-improvement and Internet bookmarks.
• Workflowy - Was on hiatus, but I came back to it recently. It's an excellent thought capture tool.
• Evernote - for note-taking (all non-actionable reference stuff goes here). I use premium, PIN-protected.
• Slack - an excellent chat for work.

Some of the apps I use (Trello, Workflowy, Google Docs) are in your "not used" or "second-tier" bins, but I find them absolutely indispensable.

Another point is that I use mostly cloud-based apps, so if my phone gets lost or stolen, I still have access to my data. The phone is essentially disposable.