Well I think there should be a list available somewhere, at least the official list of example sites should be updated, I’m sure there are great sites out there, but they are hard to find. One could get the idea that it is not popular and give up installing bbpress
Make sure that forum example you trying to mimic or address as sample is using the latest bbPress. Since many nice looking themes for bbPress is only compatible with old version, so you won’t be disappointing at the end
An example of bbpress forum is that you can see the icon of bbpress in the footer or header and also it gives the nofollow link but get a do-follow link with seo experts company karachi at a cheap rate.