These incredibly small surface-mount LEDs are an easy way to add a lot of very tiny (but bright!) colorful dots to your project. They are just
Multiple led stips from one Arduino - Project Guidance - Arduino Forum
DotStar Micro LEDs (APA102–2020) - Smart SMD RGB LED - 10 pack
Adafruit NeoPixel Mini PCB - Pack of 5 [ADA1612]
Adafruit Industries - 4957 - NeoPixel Mini 3535 RGB LEDs w/ Integrated Driver Chip - Black - RS
Optoelectronics/Light - Parallax
Arduino - Controlling a WS2812 LED strand with NeoPixel or FastLED
FastLED and Neopixel, I'm new to arduino programming and working on a personal project
NEOPIXEL Pro Max : 11 Steps (with Pictures) - Instructables
Adafruit NeoPixel Ring - 12 x 5050 RGB LED with Integrated Drivers [ADA1643] : Industrial & Scientific
BTF-LIGHTING WS2812B 100PCS 5050SMD Individually Addressable Smart RGB LED Pixel for Arduino 5V DC Single 1-led LED Module Pixels Color Light little rgb LEDs Lampon Black Heat Sink PCB Board Only
Make your own smart LED arrangement with the same fancy side light integrated LED that is used in Adafruit's HalloWing M4, and side-emitting NeoPixel
NeoPixel Side-Light RGB LED w/ Integrated Driver Chip - 10-pack
Neopixels
NeoPixel Nano 2427 RGB LEDs w/ Integrated Driver Chip - 10 Pack : ID 3484 : $4.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Gikfun LEDs Diffused RGB Common Anode 4 Pins 10mm Super Bright Bulb Lamp for Arduino (Pack of 10pcs) EK1721