Conversation so far:
What did Phil Hartman do in Phil Hartman's early career?
Working alone as a graphic artist, Hartman frequently amused himself with "flights of voice fantasies".
What did he do as a graphic artist?
CANNOTANSWER.
What were the voices he did to amuse himself?
Hartman recorded a number of voice-over roles.
These included appearances on The Smurfs, Challenge of the GoBots.

Question: What other shows was he on?
Self-contained rewrite: What other shows was Phil Hartman on in addition to The Smurfs and Challenge of the GoBots?