Here’s one I’ve been waiting for, 5.8 million records from 28 historical record collections of Jewish historical records as detailed in this blog post.
For the UK, there’s an index of death and burial records from 1733 to 2012 totalling 78,904 records. I already discovered the burial of a g-g-uncle and verified others.
For Ireland, there’s a birth index with 61,503 records.
The single largest part of the collection is BMD records for Hungary, 2,266,404 records.