Lately I am working using icestorm!
I know very few people know it, mainly beacuse not a lot of us works with FPGAs.
It is foundamental for the open source scene because is the only FOSS that gives you the ability to "compile" for FPGAs, otherwise you would have to use some proprietary tool.
People are building lot of things on top of that, and I hope more people start workin with FPGAs: dealing with them is still quite hard, especially if compared with MCU programming.
I am sure that in very few years we will see something very interesting in that field.