For a failed SD card, look for a specialist that explicitly handles flash-memory recovery, not just hard drives. A reputable service should be able to deal with physically failed cards by removing the memory chips, reading the raw data with specialized hardware, and reconstructing the files afterward.

From the community response, DriveSavers is one well-known example of this kind of company.

As for success rates, there isn’t a reliable percentage anyone can promise in advance. Recovery depends on how the card failed: logical corruption can be easier, while severe physical or memory-chip damage can greatly reduce the chances. A trustworthy firm should evaluate the card first and explain the likely outcome rather than guarantee a specific recovery rate.

Important: stop trying software tools and don’t keep powering or writing to the card, since further attempts can reduce the chance of recovery.