There is a lot here, and even a new one showing Devourers for Tyranids. These come from several different places, and where there was just too much, I left links for you to look further.
http://casuallygrimdarkblog.blogspot.com.au/2017/10/tyranid-rules-leak-devourers-are-back.html?m=1
https://war-of-sigmar.herokuapp.com/bloggings/2519
or here where I believe they originally come from.
https://imgur.com/a/QKg3E
There is a lot of pics here, that I just could not show them all.