Select text by holding Shift whilst sliding spacebar (i.e. Spacebar acts like a trackpad on a laptop)
It would be great if holding down the Shift key whilst dragging the spacebar selected the text! (i.e., when you hold down shift, the spacebar effectively becomes the same as a trackpad). Perhaps Caps Lock or Option-Lock might also enable this.
Selecting text by holding shift and moving was one of the first things we wanted to do in the keyboard. Sadly, Apple does not permit third-party keyboards to modify the selection. We have requested this functionality to no avail.