Often, your lists represent some kind of data.

You can just pass the original list data to the ImplicitlyAnimatedList as well as an itemBuilder for building a widget from one data point and it'll animate whenever the data changes:

ImplicitlyAnimatedList(
  // When you change items of this list and hot reload, the list animates. 
  itemData: [1, 2, 3, 4],
  itemBuilder: (_, number) => ListTile(title: Text('$number')),
),

It works with all classes and works well with StreamBuilder:

class User {
  String firstName;
  String lastName;

  // The ImplicitlyAnimatedList uses the == operator to compare items.
  bool operator== (Object other) => other is User
    && firstName == other.firstName
    && lastName == other.lastName;
}

...

StreamBuilder<List<User>>(
  stream: someSource.usersStream,
  builder: (context, snapshot) {
    if (!snapshot.hasData) {
      return ...;
    }
    return ImplicitlyAnimatedList(
      itemData: snapshot.data,
      itemBuilder: (context, user) {
        return ListTile(title: Text('${user.firstName} ${user.lastName}'));
      }
    );
  }
),

Here's an example that generates random numbers and animates from one state to the next (notice it's only 10 fps because of being a gif):