Stoppers and extractors
Wing fence (normally at half-span) stops spanwise flow of the boundary layer. It's normally situate at half to 2/3rds span and extends no further rearwards than mid-chord. Its spanwise leak-stopper effect on the boundary layer can be reinforced by the endplate effect of a large tip-tank.
By contrast, a winglet extracts energy from the wingtip vortex and part converts the wing-tip's induced drag into a thrustworthy component. The winglet is normally optimized for cruise. In the future we may see variable incidence flow-modifying winglets.