Is it possible to make your own custom UI Kits? If not then this would be a very useful feature
You can use any XD file as a UI kit in the sense that you can copy-paste snippets from it into another file to reuse them. Are you looking to add your own files to this list on the welcome screen?
If that's what you're looking for, there's no way to do that yet. Would you mind posting that idea to our UserVoice suggestions list?
Cheers for your reply. I have just posted it in the feature request section. It will definitely be useful for agencies working for big brands or even a teams of designers needing to maintain assets. We do a lot of web work with module based design so to create these content modules and have them in the UI kits section will be really useful.