Flexible Legend Placement

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Grid[{{ContourPlot[Re[ArcCos[-x + I y]], {x, -Pi, Pi}, {y, -Pi, Pi}, 
    Contours -> Range[0.5, 2.5, 0.25], 
    FrameTicks -> {{-Pi, 0, Pi}, {-Pi, 0, Pi}}, 
    ClippingStyle -> Automatic, ColorFunction -> "Rainbow", 
    ImageSize -> 200, 
    PlotLegends -> 
     Placed[BarLegend[Automatic, LegendLayout -> "Row"], Above], 
    AspectRatio -> 1, Frame -> False, PlotRangePadding -> None], 
   ContourPlot[Re[ArcCos[-y + I x]], {x, -Pi, Pi}, {y, -Pi, Pi}, 
    Contours -> 10, FrameTicks -> {{-Pi, 0, Pi}, {-Pi, 0, Pi}}, 
    ClippingStyle -> Automatic, 
    ColorFunction -> ColorData["TemperatureMap"], ImageSize -> 200, 
    PlotLegends -> 
     Placed[BarLegend[Automatic, LegendLayout -> "Column"], After], 
    AspectRatio -> 1, Frame -> False, 
    PlotRangePadding -> None]}, {ContourPlot[
    Re[ArcCos[y + I x]], {x, -Pi, Pi}, {y, -Pi, Pi}, Contours -> 15, 
    FrameTicks -> {{-Pi, 0, Pi}, {-Pi, 0, Pi}}, 
    ClippingStyle -> Automatic, 
    ColorFunction -> ColorData["RedGreenSplit"], ImageSize -> 200, 
    PlotLegends -> 
     Placed[BarLegend[Automatic, LegendLayout -> "ReversedColumn"], 
      Before], AspectRatio -> 1, Frame -> False, 
    PlotRangePadding -> None], 
   ContourPlot[Re[ArcCos[x + I y]], {x, -Pi, Pi}, {y, -Pi, Pi}, 
    Contours -> 9, FrameTicks -> {{-Pi, 0, Pi}, {-Pi, 0, Pi}}, 
    ClippingStyle -> Automatic, 
    ColorFunction -> ColorData["AvocadoColors"], ImageSize -> 200, 
    PlotLegends -> 
     Placed[BarLegend[Automatic, LegendLayout -> "ReversedRow"], 
      Below], AspectRatio -> 1, Frame -> False, 
    PlotRangePadding -> None]}}, 
 Alignment -> {{Right, Left}, {Bottom, Top}}]

Control the location and orientation of legends.

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