Doctor Harleen Quinzell
Morpheus was called Sandman, yeah, but technically speaking he isn't the same variety of Sandman and continuity wise he predates Dodds by several million years. Though Daniel is quite happy to name himself as 'Sandman' when talking to the JLA as he thinks it easier to put things in nice Superheroey terms they'll understand.
Kirby's Hector Hall Sandman is revealed in the Gaiman series to have been set up as 'Sandman' by Brute and Glob, and Morpheus's reaction to his use of the name suggests that he saw himself alone as having legitimate claim to it - although he never seemed to have a problem with Wesley Dodds' using the name, perhaps since Wesley was the
universe's attempt to compensate for his decades-long imprisonment.
TIPPY-TOE SAYS: Rocky out of 'Rocky and Bulwinkle', Secret Squirrel and Slappy from 'Animainiacs' were among the universe's attempts to compensate for Squirrel Girl's decades-long imprisonment.