Possible Clues:

• Lassie, for one
• Commander for Joe Biden, e.g
• Pluto, famously
• You may take one for a walk
• Family pooch
• Toto, to Dorothy
• Home lab, say?
• Asta, to Nora
• Daisy in 'Blondie,' e.g
• Eddie of "Frasier," for one