I’m Looking for “Handy” Apps

Like most folks, I have a smartphone. With all of the apps that I use, somebody had to show me what they did and how to get them.

One of my favorite apps is called "Marco Polo." It's just video messages that you and your friends send back and forth. Then you can watch the messages when it's more convenient for you.

But I'm looking for more "handy" apps. Let me know what I'm missing.