As Dave correctly pointed out, there are different materials and styles of thrust washers. As you have not indicated what the application is, we can only give general guideance. The requirements of scale models is quite different than say gas or high speed electric monos and hydros. Those will often require and use three part caged ball bearings. On this side of the pond Octura came out with those first,( i am dating myself) but here are quite a few available brands now.