★★★★★ (851 ratings)
kboard is a powerful productivity tool that can be used alongside your regular keyboard.

Each key is customizable, and can be a word, sentence, a set of commands to execute (like a macro). It can now even get some data from the internet and send it as a message - all in one tap of a key!

Examples of uses are:

* storing repetitive messages (e.g. happy birthday)

* Custom text emoji/faces (e.g. ¯_(ツ)_/¯, ( ͡° ͜ʖ ͡°))

* retrieve and send an answer from Wolfram Alpha

* a key to convert a song title to a Youtube video

* a key that outputs a random title from a subreddit like /r/AskReddit

* convert search terms into site-specific searches.

More examples of use (and a list of available commands) on the wiki -
From version kboard 4.1.4:
* Single key/row option
* Added `curl` - create a key that outputs the result of a HTTP GET request
- examples: Wolfram Short Answers API, Cat Facts, Jokes API, Song name => Youtube Video. The world is your oyster!
All versions
February 5, 2019