We have direct Garmin and TrainingPeaks integrations. TrainingPeaks supports integration with about 20 different platforms.
You can download MRC, ERG and ZWO files to use in a lot of different training apps and devices. GoldenCheetah works with ANT+ on PC or Mac and is free. I have heard ERGVideo has a solid free-version for PC that also supports importing files. Zwift, TrainerRoad and Wahoo are the other major apps/devices that you can import these files into. Rouvy also supports importing MRC files but does not support ramps in workouts. I will try to keep up dating this list. I know there is a lot more.