Quantity   Component name
1 × Raspberry Pi Zero W https://shop.pimoroni.com/products/raspberry-pi-zero-wh-with-pre-soldered-header
1 × NeoPixel Breakout Board (such as the PixelLeaf) https://www.tindie.com/products/oakdevtech/5x10-pixelleaf-rgb-matrix-sk6812mini-rgb-matrix/
1 × Alternative: Pimoroni Blinkt! pHat https://shop.pimoroni.com/products/blinkt
1 × On/Off switch I usually just find one from old toys, discarded decorations... they're everywhere.
1 × USB power & cables The official Raspberry Pi version (https://www.adafruit.com/product/4298) gives you 3A - which is more than enough. You may need an extension cable.
1 × Enclosure A printable one is available at https://www.thingiverse.com/thing:4590885 - but you can use anything that exposes the GPIO ports and has room for a Pi Bonnet