Base Building games with Tower Defense elements?

So I was planning to play this game (Nine Stones) but before I do and invest a lot of time on this one maybe some of you can suggest me other good game for Mobile that is Base Building and has a Tower Defense elements on it?

P.S: Please no Clash of Clan. I've already played it and enjoyed it for three months, I think, before I dropped it. Also it's better if its free-to-play so I can try it first too.