As KochiKame is a very popular anime and manga series, there are many references (parodies) to the series in other manga and anime. Other characters have also made cameos in the KochiKame series as well.
Crayon Shin-chan[]
Yoshito Usui drew this manga page for the 30 year anniversary of KochiKame.
Nakagawa doing the elephant dance in episode 103 of KochiKame
Yūsei Matsui[]
In this story Yūsei Matsui's author avatar give his own eulogy to the kochikame series while his creations (the characters from assassination classroom and Neuro: Supernatural Detective) come to deal with the series departure as Korosensei and Neuro fights each other to determine which of their favorite character is superior Tōden Hoshi or Kankichi Ryotsu.
The Disastrous Life of Saiki K.[]
Volume 8 of The Disastrous Life of Saiki K.