I am a bit surprised to find Bollinger Bands in the "Volatility" Category. The idea/math behind bolinger bands is based on a relationship between Trend (could we call it Drift?) and volatility, so it does not belong in neither Category.
I'd suggest to start a cetegory "Bands" or "Channels" for all these animals.
Furthermore I've seen quite some "Indicators" which serve more graphical purposes and are hardly useful in a programmed strategy. (Trendlines, Detrended Price Oscillator,...)
I'd suggest to create a category "Graphical" or "Charting" (in its worst sense) for them.
Should simplify searches...
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