Hello there @Kasha! As a fellow plus sized woman, I am happy to weigh in on this subject!
Not knowing exactly what size you are looking for, I can at least let you know what has worked for me. Starting with what is available through REI, I cannot say enough good things about the Brooks Maia Bra. It has been my favorite for years. No need to pull a bra awkwardly overhead and risk getting tangled or strangled! Equally great is the Brooks Fiona Bra. If you can't find these in the right size for you through REI, I would take a look at Brooks directly.
The last one I have to recommend is the SheFit Bra. I found this bra during quarantine and I love it so much. I saw it on Instagram so many times and wasn't sure it was worth the hype. I think it is! I love the adjustability and the fact that it zips in the front making it the easiest to get in and out of!
Hope this info helps and that some other ladies will be willing to offer additional suggestions!
If you're looking for a cup size of E or lower, I'd also like to suggest:
Lululemon Enlite Zip Front Bra: Very comfortable, and fairly supportive. It's a seamless construction, however, which means you have to be very, very careful never to put them in the dryer, which can cause the welds to separate over time.
I took a chance on these bras and was quite surprised and satisfied with their level of support for running! The Target bras go up to 42 DDD and 44 DDD respectfully.
If you need a cup size larger than E, I'd second the recommendation for SheFit! My sister convinced me to order one (en route to me now!) They don't follow traditional cup and band sizing, so you'll have to measure your bust and rib cage at home prior to placing an order. From there, she said that it takes a minute to dial in the band and strap adjustments, but that she's noticed very little motion while running.
Hope this helps!
@Kasha - My wife has had a great experience with SheFit, especially for higher impact and aerobic workouts. The sizes are non-traditional but she didn't find it difficult to get the right fit. For lower intensity, she swears by Girlfriend Collective.
If you're willing (or know someone else who is!) to help our product designers out, they have posted a survey here in the community and would really appreciate it if you could take a few minutes to provide some input:
If you are looking for a less expensive, but still super comfortable and supportive option - I have recently discovered the Dip brand at Fred Meyer, and the Sports Bras come in sizes to fit from xs to 4x and are $24-34. They are awesome! I bought one as a test - loved it so much I went back and bought 2 more. They also have other plus size athletic gear - I bought a pair of moisture wick leggings, but haven't got to really test them out yet.