One of the best third-party keyboards on the Play Store is SwiftKey, and its popularity can be put down to its great customization options and constant development. The beta channel is the first place to get new features, and the latest update includes a 'Quick Paste' option and built-in location sharing.
The app recently added a nifty photo themes feature that lets you set a background image of your choosing. In the latest update, 'Quick Paste' shows you copied text in the prediction bar so you can see exactly what you've got copied and paste it easily. The new in-app location sharing option will only be available to US users to begin with.
Once you copy some text (left) it then appears in the prediction bar (right).
You can see the full changelog below:
There are a few other improvements in version 188.8.131.52, such as new languages and layouts. SwiftKey Beta can be updated via the Play Store, or you can sideload it via APKMirror.