Tamarian language has a number of in-universe phrases, with "Darmok and Jalad at Tanagra", "Sokath, his eyes open", and "Shaka, when the walls fell" being probably the most popular.
Which phrases would be in the language, if Star Trek was used the source for myths and metaphors? Here are a couple of examples that I've either seen somewhere else or came up with myself.
"Sisko, his plan thwarted." – when something is fake (scene from "In the Pale Moonlight").
"Q's present to Data" "Q's gift to Data" – laughter (from this scene)