Juvenilia
Etymology
Latin, the neuter plural of "juvenilis," youthful, from "juvenis," a young person. It names the poems, drawings, and stories made before a talent came fully into its own.
noun · /joo-vuh-NIL-ee-uh/
The early works an artist or writer produced in youth, judged against their mature output.
What it names
It gives a name to the apprentice work that reveals a talent still forming, before its later voice arrived.
Example
The retrospective opened with juvenilia — clumsy teenage sketches that already hinted at the master’s later line.
Related idea
Formed like ephemera, a Latin plural naming a whole category of minor works; juvenilia is prized for what it exposes about a talent in the making.