Some examples of the names arguably cited in this way include:
• Simon of Cyrene, the father of Alexander and Rufus
• Joseph of Arimathea; Simon the leper in Bethany; the healed blind man Bartimaeus (and Luke’s Zaccheus) in Jericho; the synagogue official Jairus and the tax collector Levi, the son of Alphaeus, in Capernaum et al.
• Mary Magdalene
They would get cited via odd inclusion in the narrative, or arguably through what Bauckham calls an "inclusio" (e.g. he argues Mark's gospel does this with Peter's name).
Early Christian sources which seemed to cite witnessesincluded the Jerusalem church (e.g. in the 1 Corinthians 15 creed and the gospel stories it propogated). We see this in the Gospels, as Greco-Roman biographies. We also knoew that Paul cited names (e.g. through the 1 Cor 15 creed, while adding “some of whom remain”).
For more: Papias says the apostle's proteges still teach in their name. (James Dunn: “R. Bauckham, …, deduces quite fairly from Papias that ‘oral traditions of the words and deeds of Jesus were attached to specific named eyewitnesses’; [On History, Memory and Eyewitnesses: In Response to Bengt Holmberg and Samuel Byrskog. Journal for the Study of the New Testament, 26(4) (2004): 473–487. ]
We see the Gospels doing this with some regularity in how the appeal-cit to witnesses, which its a common feature in Greco-Roman biographies like the Gospels. For example, there is an argument that stories with named witnesses happen to be the most vivid stories (e.g. the story of the rising of Jairus's daguther, of Zacchaeus, of Cleopas and his companion, and the healing of Bartimaeus), and the correspondence is unlikely to be a coincidence. In fact, it makes best sense if the named witnesses were the regular 1st hand tellers and tradents of the story they witnessed, a model with a lot of independent support.