CodeWriter Packages 
Tri Inspector · 
Free and open-source library that improves unity inspector.
UniMob · 
Modern reactive programming library. UniMob inspired by MobX and adapts the principles of object-oriented reactive programming for Unity.
// declare reactive property
[Atom] private int Counter { get; set; }
// Print message when Counter changed until Lifetime terminated
Atom.Reaction(Lifetime, () => Debug.Log("Tap count: " + Counter));UniMob.UI · 
MVU/MVI/Redux like library for building declarative user interface in Unity. Built over UniMob. Inspired by Flutter.
private Widget BuildTodos(BuildContext context) {
return new ScrollList {
MainAxisAlignment = MainAxisAlignment.Start,
CrossAxisAlignment = CrossAxisAlignment.Center,
Children = {
_todoList.Todos.Where(todo => todo.Finished).Select(todo => new TodoWidget(todo.Id))
}
};
}More examples can be found in the UniMob Samples repository