Brand
First I will say that I personally don't use indicators, but to answer your question. Indicators fall into 2 main camps: trend-following and momentum and the most appropriate ones to use depend on your style of trading.
Trend following, such as MA, lag market action, but are useful to indicate the broader picture and to filter out noise. Momentum indicators such as RSI and Sochastic are designed to identify the pace of market action and attempt to provide buy/sell signals at times when the rate of activity in a particular direction is changing. Its like measuring the acceleration/decceleration. They are used in swing trading to identify turning points.
Fibs were mentioned earlier in the thread. I don't regard these in the same light as indicators because they are based on a set of external parameters i.e. the fib numbers. If you believe in them then they, too, are predictive.
Indicators are derivatives of price e.g. averages or even averages of averages. That is why I and many traders on T2W don't use them, but like all these things if they work for you then fine.
Charlton