I want to find all matches of consecutive digits and I use the regex “\d\d” for that. However, it only returns 4 matches (45,56, 67, 89). Expected output is 6 matches (45, 55, 56, 67, 78, 89). How do I achieve that?

So it seems what you really want is all the 2 digits numbers and not consecutive numbers. Because consecutive numbers would include 455, 4556, 556, 678, 6789, and 789.