Possible Clues:

• Some folk acts
• The Carpenters and Sonny & Cher
• Many comedy teams
• The Smothers Brothers and others
• The Righteous Brothers and the Everly Brothers
• Teams of two
• Two pairs?
• What 17-, 25-, 37-, 52- and 62-Across are, themewise
• Some acts
• Two-person bands