Check the following:

1. http://crcns.org/data-sets

2. For EEG/ERP: https://sccn.ucsd.edu/~arno/fam2data/publicly_available_EEG_data.html

3. http://www.brainsignals.de

4. http://bnci-horizon-2020.eu/database/data-sets

Thanks Bahman, It was helpful :)

GIN is a another great repository - this one in particular has massively parallel data recorded in macaque during motor tasks.

https://doid.gin.g-node.org/f83565d148510fede8a277f660e1a419/

Thanks for the reference Angela, it was a nice paper :)

ECoG database:

https://exhibits.stanford.edu/data/catalog/zk881ps0522