ReptiChips for bigger chunkier stuff and Reptile Prime for a midsize substrate. I hate recommending Reptile Prime but not going to lie, Dottie seems to love the stuff. It isnt dust free like the claim though but it is lower on the scale, about equivalent to ReptiChips. The killer is the price. The stuff is easily the most expensive on the market and if you have more than a couple snakes, be prepared to shell out cash. I only use it for Dottie as it would cost me over $100 a month just for substrate for all my snakes if i used that stuff exclusively. Plus i think it too fine for larger snakes. I recommend cypress for large stuff like adult boas and retics and burm etc.
And personally i would not recommend any fine coco substrate as it seems the finer the grade, the more the dust.
Eco Earth has a patented process that makes it dust free.
ReptiBark makes a good and easy to clean humidity holding substrate as well.