I prayed the 'Id prayer with the Prophet (ﷺ) not once or twice (but many times) without the adhan and the iqamah.
Sunan Abi Dawud Book 2, Hadith 759
← Previous Hadith The Messenger of Allah (ﷺ) offered the 'Id prayer without the adhan and the iqamah. AbuBakr and Umar or Uthman also did so. The narrator Yahya is doubtful about Uthman.

Sunan Abi Dawud Book 2, Hadith 758 Next Hadith → The Messenger of Allah (ﷺ) would say the takbir (Allah is most great) seven times in the first rak'ah and five times in the second rak'ah on the day of the breaking of the fast and on the day of sacrifice (on the occasion of both the 'Id prayers, the two festivals).

Sunan Abi Dawud Book 2, Hadith 760