algorithms implemented in scikit-learn

https://scikit-learn.org/stable/modules/outlier_detection.html

https://scikit-learn.org/stable/auto_examples/miscellaneous/plot_anomaly_comparison.html#sphx-glr-auto-examples-miscellaneous-plot-anomaly-comparison-py

4 Automatic Outlier Detection Algorithms in Python

https://machinelearningmastery.com/model-based-outlier-detection-and-removal-in-python/

Among algorithms above, Covariance method or Minimum Covariance Determinant (MCD) seems to be related with PCA.
See the following:

https://onlinelibrary.wiley.com/doi/full/10.1002/widm.1236