A modern improviser that uses microtonal scales a lot is guitarist Dave "Fuze" Fiucynski: https://www.youtube.com/watch?v=EWM6xRGoGcQ https://www.youtube.com/w

A modern improviser that uses microtonal scales a lot is guitarist Dave "Fuze" Fiucynski: https://www.youtube.com/watch?v=EWM6xRGoGcQ https://www.youtube.com/watch?v=EWM6xRGoGcQ https://www.youtube.com/watch?v=KWxV7u8Zm4I&ab_channel=BerkleeCollegeofMusic https://www.youtube.com/watch?v=KWxV7u8Zm4I&ab_channel=Berkl... (he typically plays a double neck guitar, one with standard tuning/frets, the other fretless)