I'm making an asparagus ravioli - what kind of sauce would pair well with asparagus? Maybe a lemon brown butter? Good herbs to include?

I second the tarragon suggestion. Asparagus is so sweet this time of year - I'd want to let it shine. Good butter, a bit of tarragon sprinkled over the finished dish ... And a lovely wine, of course!

Asparagus is a difficult vegetable to find a good herbal mate for. Chervil does work. Brown butter is not a bad idea at all, especially if you melt some good quality chopped anchovies in there, or alternatively add some salt packed capers. Those would compliment a ravioli. Prosciutto is a good match or simply seasoned bread crumbs sauteed in butter or olive oil.

Browned Butter with Fried Sage would be wonderful. Tarragon and Chervil would work well also.

Sage. I love sage with ravioli, plus it looks so pretty.

Is the asparagus in the ravioli or is it chopped up and mixed with ravioli (like cheese ravioli)? I don't think it makes much of a difference either way, but just curious. Some things that I always find to go well with asparagus: tomatoes, roasted red peppers, lemon, parmesan cheese, roasted onions, roasted garlic... hmmm... looks like I'm winding up to recommend a romesco sauce. Just roast tomatoes, red peppers, onions, garlic in a baking pan, and while you're doing that, pan-roast some bread and almonds. Mix everything together in a blender, maybe add some parmesan cheese and a spritz of lemon, and it makes a great red sauce! :)

Oddly enough, I think a hollandaise would be nice. Maybe make a thinner hollandaise?