Hello Anthony, some filters might not be viable at this point due to the awful database schema bbPress has (ie, it has none, it relies on meta tables), and some complex queries required for roles are simply too slow.

But, I will be expanding list of available filters in the future versions, starting with few filters related to my GD bbPress Toolbox Pro plugin and some of its features that can help to search for posts in the forum. And, I will see what else can be cached to speed up some more complex filters.

And, in the next version, the plugin will allow for coding custom filters for other developers to use.