[SparkyMcUnicorn]

Any of these should work.

https://github.com/Helium314/HeliBoard

https://github.com/openboard-team/openboard

https://github.com/rkkr/simple-keyboard (guessing, since AOSP Keyboard works and this is a fork)

Not open source: https://www.microsoft.com/en-us/swiftkey

Does not have glide/swipe (reserved for symbols), but I just installed and giving it a shot: https://github.com/Julow/Unexpected-Keyboard

[Grimblewald]

Unexpected keyboard is unexpectedly awesome. Looks a bit dated, but boy does it have some functionality packed into it.

[nine_k]

My choice is https://github.com/AnySoftKeyboard/AnySoftKeyboard/

It does have glide typing, even.though I don't use it.

It rather uses long-tap to access multiple symbols, and can be split or pushed to a corner on devices with a big screen.