* Theodoros Kolokotronis: A key figure in the Greek War of Independence, Kolokotronis was a skilled military leader, but also known for his ruthless tactics and involvement in political intrigue. He was eventually imprisoned and executed by his own government.
* Vassilis Paleokostas: A notorious robber baron and bandit leader of the early 20th century, Paleokostas became a folk hero for his daring raids and Robin Hood-esque reputation.
* The "Golden Dawn" Party: Though not a single individual, this far-right, neo-Nazi political party gained notoriety for its violent activities and association with criminal acts.
* Various individuals involved in the "Greek economic crisis": Many public figures, including bankers and politicians, were implicated in various scandals and crimes related to the financial collapse of Greece.
It's worth noting that many of these individuals, particularly the historical figures, are considered more as controversial figures than "criminals" in the modern sense. Their actions were often motivated by political or social circumstances of their time.
Ultimately, the "most famous" Greek criminal is a matter of perspective and interpretation, and the answer will likely vary depending on who you ask.