Do I have room to add a 50 amp breaker?
When you define "50A" breaker it is really necessary to specify if it is for a 110VAC circuit or for a 220VAC circuit. Common usages for a 50A breaker is for a 220VAC circuit to support:


Electric kitchen range / oven
Electric water heater
RV hookup
Electric car charging port


With that said the 220VAC/50A breaker would be a two pole unit similar to the existing 30A breakers that have the connected (bridged handle) across the two poles.

It appears plausible that such dual pole breaker would fit in the two remaining spots in the lower left corner of the panel. I say plausible because there is some question about just how the panel's bus bus bars are configured considering the existing placement of the two pairs of 30A breakers on the left side that have bridged handles. You may want to have the electrician come out to give a bid on the work and its ultimate feasibility before you commit to the work.