What breakers will a midwest panel accept?

https://www.brookelectrical.com/Imag..._Specsheet.pdf

Not necessarily what breakers fit but what APPROVED breakers. Putting in an unapproved breaker voids the UL listing. I see panelboards with 3 or 4 different breakers. Yes, they fit but are not approved. Home Depot used to have a listing in their store that showed approved breakers, not sure if they still do. Unless the circuit breaker is marked on the panelboard as being acceptable or it is UL Classified as being acceptable, the circuit breakers have not been tested in the panelboards and should not be used. Might be better to consider a new panelboard.

Circuit Breakers approved or "Listed" for use in a panel are specifically listed on the panel cover door or in the manufacturers documentation.