There isn't a single "best" indicator for cryptocurrency trading, as different indicators serve different purposes and traders may have varying preferences. The choice of an indicator depends on your trading strategy, risk tolerance, and the specific cryptocurrency you are trading. Here are a few popular indicators often used in cryptocurrency trading:

1. **Moving Averages (MA)**: These indicators smooth out price data to identify trends. The Simple Moving Average (SMA) and the Exponential Moving Average (EMA) are commonly used.

2. **Relative Strength Index (RSI)**: RSI measures the speed and change of price movements. It helps identify overbought or oversold conditions, potentially signaling a reversal.

3. **Moving Average Convergence Divergence (MACD)**: This indicator combines moving averages to identify potential trend changes and momentum shifts.

4. **Bollinger Bands**: Bollinger Bands consist of a moving average and two standard deviation lines above and below it. They help identify volatility and potential price breakouts.

5. **Ichimoku Cloud**: This indicator provides multiple pieces of information, including support and resistance levels, trend direction, and momentum.

6. **Volume**: While not a traditional indicator, trading volume can be crucial in confirming price movements and trends.

7. **Fibonacci Retracement**: This tool helps identify potential support and resistance levels based on Fibonacci ratios, which are derived from the Fibonacci sequence.

8. **Stochastic Oscillator**: This indicator compares a cryptocurrency's closing price to its price range over a set period to determine momentum and potential trend reversals.

Remember that no indicator is foolproof, and they work best when used in combination with other indicators and analysis methods. It's also important to adapt your strategy to the specific characteristics of the cryptocurrency market, which can be highly volatile and influenced by various factors.