My own photos. I have one bra like this. It's the only type/style I've ever found comfortable and flattering (outside of sports bras) but it was a present from an ex, and I have never seen or come across another one.
Not sure if visible properly but it doesn't have defined 'cups', has a small amount of stretch and a thick/wide band under the cups and around the back.
Is there a term I can search to find some similar bras?