Echoing Boon

Standard	Not Legal
Pioneer	Not Legal
Modern	Not Legal
Legacy	Banned since August 26, 2016
Vintage	Banned since August 26, 2016
Commander	Banned since August 26, 2016
Pauper	Never Banned
Oathbreaker	Banned since June 19, 2018
Extended	Not Legal

View on Scryfall

Timeline

• August 26, 2016 - Status changed to Banned in Vintage
• August 26, 2016 - Status changed to Banned in Legacy
• August 26, 2016 - Status changed to Banned in Commander
• August 26, 2016 - Released
• June 19, 2018 - Status changed to Banned in Oathbreaker

Rationale

Echoing Boon is a Conspiracy card, which was designed exclusively for the draft format. As a result, all Conspiracy cards were pre-emptively banned in all constructed formats upon release.