Beastie:

Scottish National Dictionary (1700–)

BEASTIE, n., dim. of beast. [′bisti]

1. Familiar and affectionate contraction of beast

Bestiary:

Oxford English Dictionary (1884–)

BESTIARY, n., [ˈbɛstɪəri]

1. a descriptive or anecdotal treatise on various kinds of animal, especially a medieval work with a moralizing tone.

An investigation into the folklore and monsters of Scotland by collecting stories and tales of creatures and illustrating one a day, every day in November 2020.

You can buy a printed copy of the BeastieAry on my online store below