Marvelous Guide to Critical Creatures Vol. 1

From publisher blurb:

In this book, these new abilities will all be categorized as Critical Abilities, making them separate from reactions, bonus actions, and normal actions for the purpose of action economy. In addition, each of these new abilities fall into one of the following categories: movement, attack, and ability. All movement abilities provoke attack of opportunity following the normal rules unless they say otherwise. You may pick one of the three abilities when you score a critical hit.