We are excited to announce a new feature on the Hub: Favorites!
You can now add resources to your favorites, and organize your favorites into collections!
You can check out the details in our official announcement!
The only way is to use a "fake" floor using something that the hair does collide with setting the materials to hidden in the shader tab of the textures. The built in slate floor works for this.
You can scale and embed that slate in something else, like a table or sofa. Not all hair models work well with that trick. Some work better than others.