Kuroba (Kaito and Toichi's family name) is also a way to pronounce "clover" in Japanese. This is most likely why a clover appears on Kaitou Kid's monocle.
In both the Japanese and English dub, Kaito Kuroba/Kaitou Kid shares the same voice actor as that of Shinichi Kudo.
Kaitou Kid signs his heist notes with a drawing of his face in abstract. He re-draws this insignia for each note, so that police will know that it was truly him and not an imitator using a scanned copy of a former insignia.
Originally referred to as Kaitou 1412, Yusaku Kudo saw a reporter's hastily scribbled "1412" on a piece of paper and purposely misread it as "KID". Thus, Yusaku named the Kaitou Kid.