Let us take an adapted example from Mathematica doc's:
p=Show[ListLinePlot[Table[Accumulate[RandomReal[{-1, 1}, 250]], {3}],
Filling -> Axis, PlotLegends -> {"one", "two", "three"}]]
Export["plot.pdf", p];
I will have several graphs with the same legend so I want to export it separately and use only once in my latex file. Sure, I could export all but one plot without the legend but then the size of one plot will be different, I would have to adjust fonts etc. How to achieve that?