Since there is nothing official available to purchase yet, I was tempted to buy a kind of Making of Romulus booklet for the poor haha. It's really nothing special and pretty simply cobbled together.
We already know most of it from the internet. the thing is called beforeesandafters and
It's a kind of slimmed down Cinefex version printed on cheap paper.
It is also mentioned here which department was responsible for which effect.
Studio Gillies notably made the Offspring Egg and the Chestburster. Legacy the Xenos, Weta the Huggers and Offspring. But even that was already largely known from the internet, so this "work" doesn't actually tell us much that's new.
There are at least a few nice interviews and photos that I didn't know about. for the collection.