Gemma Starter Pack is awesome for getting started with Adafruit GEMMA and wearable electronics. Everything you need to make a basic project is included in the pack. There's a GEMMA board, four sewable bright RGB pixels, a battery holder, 2-ply conductive thread, alligator clips to help you test out your circuit, and a USB cable for programming GEMMA.
The pack includes:
GEMMA V2 miniature wearable electronic platform
4x Flora RGB NeoPixels V2
Coin cell battery holder with JST connector and on/off switch