Welcome to Share Your Tools on WeBrain!
WeBrain example datasets:
Info of example data: read_me.txt
One zip file one subject: sub_001.zipsub_002.zip
One zip file multiple subjects : sub_01-02.zip
P300 example raw EEG data (S22 is target stimulus, S222 is correct-reaction marker): ERPdata_sub_01.zip
EEGPipe Demo dataEEG_Resting_data
Open EEG Datasets:

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 

Canadian Brain Imaging Research Platform (CBRAIN): http://mcin-cnim.ca/technology/cbrain/