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