Best brands for magnesium and B complex?

So I've got a load of issues (MTHFR, slow COMT, bipolar, chronic fatigue, a few others) and my psychiatrist, therapist, and I have come to the conclusion that I need to start with magnesium glycinate and a B complex. I need to be careful about methylated B vitamins though. There's an unbelievable number of brands and I have no idea what I'm looking for. I know some aren't super reliable. Please give me any that I should definitely try and/or avoid! TIA