Mushoku Tensei started airing season 2 today. I'll watch it a little later today, but I really liked season 1 (and the book), so my hopes are high.
The season has officially started. 7 or 8 new shows have already aired so far.
EDIT: Ok, so I watched the new episode of Mushoku Tensei (episode 00), and it appeared to be filler. I don't recall ever reading a story like that in the books. Maybe the author added it later, but it wasn't a piece of the web series that I read originally. That said, it wasn't "bad", per say, but it isn't what I was expecting. I look forward to the real first episode, though.