What are the confirmed and agreed-upon Sunnahs among the majority of scholars regarding the description of prayer, in terms of sayings, actions, and postures?

The jurists have agreed upon the supererogatory nature of some actions in prayer, among them: raising the hands during the opening takbir, reciting surahs in the first two rak'ahs of the obligatory prayer, saying "Ameen" after reciting Al-Fatiha, the worshiper straightening his back and neck during ruku, and increasing the duration of طمأنينة (stillness/tranquility) beyond the obligatory measure.