Some sources of machine learning data

• MLData.org
• Dr. Gashler's collection of datasets
• A fork of Dr. Gashler's collection
• Financial dataset search engine
• Causality datasets
• A list of facial recognition datasets
• Some NLP and data mining datasets
• Datasets for NLP
• Data Market (lots of time-series data)
• Weather data
• Deep learning datasets (hard non-linearly-separable data)
• Street view house numbers
• Weka datasets
• CMU stats datasets
• KD Nuggets datasets
• Datahub.io
• arXiv data