https://www.elderscrollsbote.de/sets/
https://eso-sets.com/
https://elderscrollsonline.wiki.fextralife.com/Sets
You'll find all set related infos at websites and are able to read where and how they drop, what stats they need, which DLC added them etc.
Julianos can be crafted, you need to research some traits to be able to build them.
If you search for an addon providing you an ingame sets list with search methods and drop location information you can try:
WishList
It provides a sets search tab as well as your WishList for your toons where you are able to add items you are searching. You'll get nmotified if an item on your WishLists drop (you or any group member) and are able to keep track of what you still need this way + where it drops -> context menus at the set search as well at the WishLists and history tabs.