As requested, here's the general monster stats page and the monster examples page. A lot of the stats are explained elsewhere in the 52 Pages; the red icons are damage types (cutting, piercing and blunt).
Unlike for humanoids and animals, I don't want to give too generic a set of rules for building weirdo monsters - although as it turns out, a lot of garden-variety hybrids and mutants can be modeled with the animals rules. My main contribution to the process: the rules for "no flesh, no vitals, no bones, no body" which reward taking a variety of weapons with you.
Because 52 pages are short I also plan on teaching by example, in the adventure design and play example pages that finish out the set. There I'll show a couple of ways monsters can be tweaked even further. There is also definitely space in the "expert" sequel for giving more details of special attacks, defenses, monster spell use and the like.
On Abstraction and Saving Throws
1 hour ago