fir2dot
A small, "hacked together in one rainy morning" FIRRTL pass which generates a Graphviz description of the module hierarchy. Because I needed it, and going the YoSys way was not good enough for me.
Graphviz - AFAIK - can't create a good rectilinear layout, the resulting graph is not really nice.
Usage in sbt:
runMain Main design.fir
where design.fir is the generated FIRRTL for your Chisel hardware.
The program will generate a .dot file for each module in the .fir description. Afterwards you can use Graphviz to lay it out.