Our very first monster is a CR 5 Giant, so we're already starting with an oft-overlooked creature type. At first glance, one might mistake the aberrant for filling the same niche as the ogre; after all, it's size Large, it's brutishly strong, it's usually evil, and it wields big clubs to smash things. On the other hand, the aberrant is as intelligent as a human and otherwise has pretty high ability scores all around (although the mental ones are still below those that grant the aberrant its physical powerhouse status).
Then, of course, there's the table-based elephant in the room: mutations. While it isn't specifically stated why, all aberrants are born with decidedly noticeable mutations that ostracize them from other giants and make them decidedly hostile to outsiders. While some of these mutations, such as one of their arms growing in an offset place or a Bigfoot-style cone head, are purely cosmetic, the majority provide some form of benefit; for instance, rolling a 4 on the d10 gives your aberrant a third eye protruding from the back of its head, granting it a bonus to Spot checks and preventing flanking.
All in all, this is a fun monster to start off with. Giants, along with Fey, hold a soft spot in my heart as monster types that don't get the limelight often enough, and one as odd as the aberrant only further gets my attention.
Holy cow, we have an eater of sapients that isn't specifically attracted to humans, elves, dwarves, or gnomes. No, this CR 7 Magical Beast feels that tieflings, demons, and celestials are what's nommilicious. It also has an arsenal of weaponry to allow its taste in meats. Never mind the fact that it's a wolf that's as big as an a lion and intelligent as an orc; no, this thing has a paralysis gaze! So, in short, you have an intelligent, oversized, paralysis beam-shooting wolf that hunts in the nightmarish landscapes of the Abyss. Yikes.
Also known as the cackle bird, the ahlinni is the first entity in this title up to bat for "really, really weird monster". A heron-like bird with a beak as long as the rest of its body, ahlinnis impale foes that they are capable of handling in melee. If outmatched, these cowardly (yes, the title specifically uses the world cowardly to describe them) avians will unleash a truly baffling breath weapon: one that imparts the spell hideous laughter. Unlike some dangerous birds from d20 titles, though, the ahlinni isn't evil or predatory, it just happens to have an obsession with gathering shiny gemstones for its mate. You know, sort of like adventurers.