OpenNeuro: 17 EEG datasets including 547 subjects. https://openneuro.org/
PhysioNet: Neuroelectric and Myoelectric Databases. https://physionet.org/about/database/#neuro
MNI Open iEEG Atlas: 1772 channels with normal brain activity from 106 subjects. https://mni-open-ieegatlas.research.mcgill.ca/
TUH
EEG: A dataset consist of 20000 clinial EEGs. https://www.isip.piconepress.com/projects/tuh_eeg/index.shtml
European Epilepsy Database: The database contains EEG datasets from ~250 patients with epilepsy. http://epilepsy-database.eu/
DEAP dataset: A dataset for emotion analysis using EEG, physiological and video signals. http://www.eecs.qmul.ac.uk/mmv/datasets/deap/readme.html
EEG data available for free: https://sccn.ucsd.edu/~arno/fam2data/publicly_available_EEG_data.html