Based on that I would look at Funatics since they seem to have the "bigger" traffic, or even AdRoll...

http://tech.adroll.com/blog/data/2014/11/17/d-is-for-data-sc...

Edit:

To be fair a lot of the companies there look like they handle heavier loads. Also Garbage Collection is optional, and there are alternatives to the "standard library" for D that others have made that are probably usable without GC. Some people have done successful embedded systems programming without the GC, I remember one guy talking about it on the D irc channel.