Struggler J. 2018. 2. 23. 18:58

[ref]

http://reference.wolfram.com/language/ref/PlotMarkers.html

https://mathematica.stackexchange.com/questions/20399/specifying-the-size-of-open-circle-plotmarkers-in-listplot


Use PlotMarkers option

ListPlot[{data1, data2, data3}, PlotMarkers -> Automatic]

Or

ListPlot[{data1, data2, data3}, PlotMarkers -> {"▲", "◆", "●"}]

Also, we can make a marker using "Graphics"

PlotMarkers -> Graphics[{Red, Thick, Circle[]},ImageSize->10]