good
羭 centers on the quality of being good, likely in a moral or virtuous sense. The single given meaning is broad, so treat it as a general positive evaluation.
羭 combines 羊 (sheep) with 俞, which may contribute a phonetic element. The exact historical development is uncertain, and the character is rare.
A sheep (羊) beside a shape that looks like a person with a boat (俞) might suggest a pastoral scene of goodness and simplicity.
For ユ, imagine a ewe (female sheep) being praised as good: ewe -> ユ, and the sheep on the left reinforces the image.