Water-based lubes are by far the most common because of their compatibility with silicone toys and latex condoms. High-quality water-based lubes may as well be called aloe-based lubes because Aloe barbadensis leaf gel is the primary thickener in almost all of them. That’s also why, when I can, I do the finger rub test first when dealing with water-based lubes. Additionally, silicone lubes can degrade silicone toys over time, so it's best to keep most of your toys away from silicone lube (though glass and stainless steel toys and silicone lube get along great). Natural oil-based lubes are becoming more common, and they typically use plant oils like coconut oil or avocado oil.