Comment by Bombinator

I saw Unexpected Keyboard recommended here, turns out it can do this as well among other things. Just tap Shift and drag left/right on spacebar. The main feature though is that you can enter the characters that aren't used commonly by swiping insted of holding on a key or switching to a different key view. You can also get Ctrl and Alt and you can like lock them as well which is useful in Termux.