This page offers a list of over 50 of the largest/most popular estate collections in the National Library. By clicking on each collection, you will be taken to the top level Catalogue record for that collection.
You will see unique GB 0210 codes for each collection. You can use these to search for collections on the Catalogue.
If the estate collection you're looking for is not listed, you can search for it in NLW Archives and Manuscripts. If you know the GB 0210 code, you can use this as your keyword to search. You can find further details on how to search the Estate Collection on our Catalogue help page.