I obtained German citizenship through my late father in 1984, after he passed away. I was dealing with the Germany consulate and told him I would have loved to have Germany citizenship. He said, 'not a problem,' and because my late father was a holocaust survivor, I was able to obtain citizenship immediatley.

So that's a category you missed. Several countries (Germany, Austria, and Poland, I think) give descendents of Holocaust survivors immedite citizenship.