I'm hesitant to mention brands. Any independently tested product with a wide variety of strains should be good. I started on Physicians Choice from Amazon and followed up with Garden of Life (not sure who sells it). During repair phase I would only eat salads made of hand shredded green and purple cabbage and kale. Equal amounts cabbage kale mixture and shredded ice berg lettuce. I used ranch dressing and added other vegetables and crushed corn chips. To each his own.
These were huge salads. I couldn't even think of eating anything else after I finished them.