Default Cydia repos do not have all the latest tweaks and packages compatible with the latest iOS version. Therefore you have to add new repos in Cydia Sources to have access to all latest stuff. I am posting here a list of the top Cydia repos which have latest packages. You can follow this step by step guide on How to add new repo in Cydia?
One of the best Cydia repo is thebigboss repo. It has access to hundreds of themes and tweaks. Please check below list and add any repo you want.
Another best repo is HackYouriPhone repo. HackYouriPhone repo has unlimited tweaks, themes, and packages to customize the complete look and feel of your iOS device. Here I have written a complete guide on How to add Hackyouriphone repo in Cydia Sources?