Here's a list of the key characters in the TV Series Picard who also appeared in another Star Trek franchise series': Jean-Luc Picard, Data, Seven of Nine, Deanna Troi, William Riker, Q, Borg Queen, and Wesley Crusher.

List the characters, sorted by the original series in which they appeared.
All of the characters first appeared on either The Next Generation or Voyager.
The Next Generation: Jean-Luc Picard, Data, Deanna Troi, William Riker, Q, and Wesley Crusher.
Voyager: Seven of Nine and Borg Queen