http://www.ats-lang.org/ [ml + c + everything dialled up to eleven. linear and dependent types. comes out of academia, but under active development and slowly beginning to gather a community.]

https://eigenstate.org/myrddin/ [not really familiar with this one but it looks interetsing. close to the metal, has pattern matching over algebraic datatypes but seems more towards the c than the ml end of the spectrum from the brief glance i took.]

http://mythryl.org/ [never took off, sadly; i really liked the looks of this one and its ambitious goals. strong sml influence, with better posix integration and some c-like surface features. developer is currently battling cancer: http://mythryl.org/pipermail/mythryl/2016-April/000942.html]

http://felix-lang.org/ [spawn of ml + c++ rather than ml + c. under enthusiastic if haphazard development.]

there have been a few others i've seen pop up over the years; i keep meaning to make a website or at least a github awesome-style list cataloguing and tracking them.