RSI based trend follower
I'm a fan of "less is more". This indicator doesn't mess up your chart with lines, symbols, moving averages or such; it doesn't even add another oscillator in a separate window, letting you focus only on what is most important: price action. It will silently do its job by plotting an arrow (upward arrow for long triggers and downward arrow for short triggers).
It works really great with strong trending markets on higher time frames, so it gives its best on Stocks on a daily/weekly frame; consider it a long term trading indicator.