I haven't found any new STO project for now. But i know a security token, it is GoldMa token.
They has raised about $8mil and built the gold mining site. The dividend distribution is start at the end of Q2 2019.
It is a waves token though, not an erc20 token. You can do the research and due diligence about the project.
I have not really seen this neither. The one I have even heard of is Bitbond, there is one aside bitbond that I saw but cant remember the name again. Although it was based on what they have on their website as an STO project that made me believe in them, I have not done proper research to really know if it is true.
I really dont like STO projects that much, I see it as projects that will be for people that can invest in a very big way, because the only way to get a very good interest from STO projects are when you out in big money, interest on small investment when I sued their calculator is very low for me.