Outliers are quite similar to peaks, so a peak detector can be useful for identifying outliers. The method described here has quite good performance using z-scores. The animation part way down the page illustrates the method signaling on outliers, or peaks.
Peaks are not always the same as outliers, but they're similar frequently.
An example is shown here:
This dataset is read from a sensor via serial communications. Occasional serial communication errors, sensor error or both lead to repeated, clearly erroneous data points. There is no statistical value in these point. They are arguably not outliers, they are errors. The z-score peak detector was able to signal on spurious data points and generated a clean resulting dataset: 