Yes, I only recently discovered the full "communities" tab and potential the other day, don't ask, it's a sloth issue! There's an awesome amount of niche communities out there waiting for people to get involved!
I just posted to the 500 words a day community, referencing this post and challenging others to make a post into a niche community tomorrow! (or today! Why not)!
Thanks again for the list, i'll be saving that for future reference, hopefully my tags will start reflecting my content more increasing the chance of it being noticed!
That's a very good idea!