Looks like you already have lots of great suggestions for finding quality supplement brands. Adding my 2 cents, I also use Pure Encapsulations, Thorne, Jarrow for Magnesium threonate and Douglas Labs for Ashwagandha (because this brand offers higher withanolide content). I use Metagenics when I can find it for certain supplements including their multivitamin and a product called SPM Active (for inflammation).
Another approach I have used for finding quality supplements, is taking a look at research studies to see which brand they're using (esp when the study isn't funded by that manufacturer). ConsumLab is a great resource, but some of the brands I have researched and settled on haven't been tested by them. I wish..