child Kirk & Spock
I’ve noticed a current sub-genre of fan art & fan fiction depicting Jim and Spock (and sometimes other crew members) meeting for the first time as children.
This trope goes way back. The first “child Spock & Kirk” story I can find is in “Eridani Triad” in June 1970.
“How I Spent My Summer Vacation” is about James Timothy Kirk’s summer visit to San Francisco, where he met a Vulcan boy named Spock, whose ambassador father was stationed at the Embassy there.