Possible Clues:

• Dungeons & Dragons game runners, for short
• Chats on Insta
• Former Ger. currency
• Channels not everyone can see
• Private chats, briefly
• D&D game runners, for short
• Private chats, briefly, and what 17-, 29-, 45-, and 61-Across literally are
• Private Discord convos
• Social media chats
• Messages on 42-Across