If you're looking for a good keyboard app with plenty of power under the hood, Gboard should be your first choice. Google's keyboard app supports voice input, handwriting, and gesture typing.

The FlickType Keyboard app is designed for typing out messages, which are then sent using Apple’s Messages app. The flow from typing in FlickType to then hitting Send, choosing your recipient, and ...

But I can definitively say that it offers a really pleasant typing experience. In fact, this is the first low-profile mechanical keyboard I've tried after using several chunky mechanical keyboards ...