Data prior to 2018 can be found here > OASIS Notices: https://www.oasis.oati.com/MISO/index.html
Recent notifications can be found on OASIS (above), as well as on the MISO website: https://www.misoenergy.org/markets-and-operations/notifications-overview/
Recorded in the monthly ROWG report, which is posted in a closed meeting -- can be found here: https://www.misoenergy.org/extranet/
Presentations on Maximum Generation Events can be found in various stakeholder meeting materials (ie: MSC, RSC, ROWG, Markets Committee of the Board of Directors, etc.)