It really depends on the size and application. For a 15" folder, I like DJI's 1552 prop (S900/S1000) which you can mount to about any motor using an adapter from KDE. T-Motor's carbon fiber props are very well made but expensive. If you are working on a new build check out DJI's propulsion systems. They offer a very good value for motor/ESC/prop combinations and their replacement props are well made and well priced.