The Flutter Proto Pack is a great way to get started with Flutter! It's chock full of neat things to hook up to Flutter, and a variety of easy to build examples will be available online soon.

The Proto Pack comes with a Flutter-compatible breadboard, plenty of jumper wires, buttons, and resistors, as well as some nice sensors and some output devices including a buzzer, servo and some LEDs.

NOTE: Control modules sold separately, pack contents subject to change.

The full item list is:
Prototyping:
Solderless Bread Board
M-M Jumper Wires
F-F Jumper Wires
Basic Resistor Set
Breadboard Buttons

Sensors:
Motion
Light
Temperature
Humidity
Magnetic Field Strength

Output:
Small Servo
Buzzer
LEDs