The various technical indicators outlined above are based on the ideas of Charles Dow, who originally used them to predict stock market prices. Various other theories of technical analysis exist, including Gann and Elliott Wave Theory. Several of the theories are loosely based on Cycle Theory, which assumes that price movements and patterns repeat themselves over time. While some of the ideas are mainstream, there is a definite lunatic fringe in cycle theory. This does not mean they are wrong.
Financial astrology is a good example.
Some of the theories are more like religions. The ratio of the length of one wave to the next is typically based on the Fibonacci numbers, ie. The ratio of succeeding numbers in the Fibonacci series gets nearer and nearer to 0.618 or 1.618 as the series goes on. Many people think Elliott Wave theory is nonsense. WD Gann was a financial astrologer who has left a body of technical ideas distinguished mainly by its obscurity.