Nik Collection is a set of photo editing plugins created by Google and later acquired by DxO. It includes various tools and filters that can be used to enhance and manipulate images in programs like Adobe Photoshop and Lightroom. The collection is known for its high-quality effects and presets that can help photographers achieve professional-looking results in their work. Some of the popular plugins in the Nik Collection include Color Efex Pro, Silver Efex Pro, and Analog Efex Pro. Overall, Nik Collection is a valuable resource for photographers looking to take their editing skills to the next level.