AR Kit
Tool for Apple developers working on virtual reality and augmented reality
AR Core
Is a software development kit for Android augmented reality
UniRx
Reactive Extensions for Unity that allows LINQ to events and more.
Entitas
Entitas is a super fast Entity Component System Framework (ECS)
Odin
Lets you expand Unity’s Editor and serialization capabilities
Behavior Designer
Behavior trees are used by AAA studios to create a lifelike AI
DOTween
is a fast, fully type-safe object-oriented animation engine for Unity
Texture Packer
Great spritesheet creation editor