One of the tricks that I do, is removing the legend out of charts into a table. To do this, I need to explicitly set the colors and/or markers for each category. In this example, to do this dynamically, I use this basic statement with a list of colors -- where the number of possible results back maybe be up to 4 distinct values.
So, in this example I put a sparkline in the table with no category or series group -- forcing it to only display one color marker. The logic that I used in the chart's marker and fill color are then also used in the sparkline, giving a legend outside of the chart.
If need be, you can just create a chart with the name and color/marker sparkline and move your legend anywhere you want.