William Overgard was a writer and cartoonist, known for working on Steve Roper and Mike Nomad. William also worked on Silverhawks. He was the writer of the following Thundercats episodes:
10. Mandora – The Evil Chaser
16. The Fireballs of Plun-Darr
23. Mandora and the Pirates
30. Dr. Dometone
36. The Thunder-Cutter
44. Sword in a Hole
85. Side Swipe
100. Exile Isle
108. The Jade Dragon
109. The Circus Train
119. Screw Loose
122. Cracker's Revenge
126. Swan Song
130. The Book of Omens