In this course, I was presented to the Quinto Elemento Lab and, for me, they already are one of the best examples of investigative journalism and of how use data elements (and their visualization) in favor of the story.
As a Brazilian and following closely the Odebrecht scandal, that originated here but it extend to many parts of the world, a history that really got my attention was "Mexico rejects 'fast track' for justice by Odebrecht" (in the link: https://quintoelab.org/project/mexico-rechaza-via-rapida-justicia-odebrecht )
It is a very complete report about the Mexico situation in the scandal, where the data is used in the text, but also in infographics that make easier to understand the information, since there is a lot it.