Above, some harmonic patterns that i often look for (bullish ones)
These patterns, when identified, have a good risk/reward ratio. They allow traders to enter into the market with minimal risk. Obviously, you need some other confirmations before taking the trade on the pattern completion.
If the point D occurs with some divergence on classic oscillators (RSI / Macd, Sto), on a bottom (or top, if pattern is bearish) of a trendline / channel, previous support/resistance levels, supply/demand zone...then there are good probabilities to see price react on the completion of the pattern.
There are plenty of patterns, but this selection, from my side, is a good start for those who want to learn harmonic pattern.
Below some examples that have worked nicely (this don't work each time, this would be too easy ;)