Ronald Sole brings up a valid case, where there can be an implied singular subject that validates the conjugation. It is possible to imagine the words missing from your example sentences:
Listen to a few examples (from a passage) which uses this letter.
Tell (us) any three examples (any one of) which shows UX design is (a) future need?
Topology examples (of a specification) which fits to the ZV4002 restrictions
Still, as written all three are awkward and not idiomatic. There is no reason to assume a secondary subject. It's more likely these are either grammatical mistakes, or they were written by non-native speakers.
In each, the singular conjugation makes more sense:
Listen to a few examples which use this letter.
Tell (us) any three examples which show UX design is (a) future need?
Topology examples which fit the ZV4002 restrictions.