Do you ever do that? If so, did you buy one or did you create one yourself? Do you use it for quick wireframe sessions or for the UI design? Thank you in advance for the insight in your design process.
For wireframes we use axure with our own made library. I think UI kits are usefull if you want to express your idea very quick. But I would not use it for a final design.
I think it limits your design creativity and you would use a lot of defaults without thinking about it ( font sizes, margins, line-height )
For me personally, I never really worked with UI Kits, but I'm thinking about creating my own UI Kit with a set of standard components so I can save some time on projects and focus more on the important sections of the website. I'm a designer at an agency and it would be a win win situation both for me and for the client who gets more out of his money since I'd be quicker with the less important stuff and could use more time working on solutions for the important areas of his product or service.