Which cryptocurrencies are more eco-friendly?

As a concerned investor in the world of cryptocurrency, I'm curious to know which digital currencies are more environmentally friendly. With the growing concern over the carbon footprint of blockchain technology, I'm eager to make more sustainable investment choices. Can you provide me with some insights into which cryptocurrencies prioritize eco-friendliness in their operations and mining processes? Are there any specific factors or metrics that I should consider when evaluating the environmental impact of a cryptocurrency?