Good question. Most pattern / signal queries tends to reflect interest in reversals.
I'm going to suggest you can only have a good continuation signal if you have a good trend in the first place, so recognising the trend is the primary requirement. After that - in real time - any price action which is not an obvious continuation of the trend direction is the start of a trend continuation pattern. In real time they all start the same way - price makes a modest counter-trend move which doesn't coincide with any dramatic newsflow or market-wide reversal.
So why not treat all trend corrective price movements as a continuation?
e.g. put in a new buy order above the high of any "down" day in a strong uptrend, without waiting for it to develop into a conventional chart pattern which then may or may not be recognisable as e.g. a flag or pennant.