In the episode "Tapestry" of TNG, Picard’s life is changed by Q. In Picard’s alternate life, who is captain of the Enterprise? Was is Jellico? Or someone else?
"Lieutenant" Picard asks Commander Data this exact question in the episode (script link):
PICARD: Who's the captain of this ship?
DATA: Captain Thomas Halloway. Perhaps I should escort you to Sickbay.
According to the Star Trek: The Next Generation Companion (as quoted by MA wiki so #grainofsalt):
"Halloway was never actually seen, and for a time the "Tapestry" writers considered referring to Edward Jellico as the Enterprise captain in the altered future. (Star Trek: The Next Generation Companion)"