Overcharts offers a wide range of drawing tools to highlight trends, supports and resistances, etc.
Trend Lines, Fibonacci Studies, Gann Studies, Pitchfork, Elliott Wave, and many others can be drawn with just a few mouse clicks.
You can Share/Synchronize a drawing tool across multiple charts (same instrument). By changing the drawing tool in any of the charts that share it, the change will be synchronized in all other charts.