Are there Sunnah practices referred to as "abandoned Sunnahs" (Sunan Mahjourah), and what is their legal status (Sunniyyah), definition, and governing principles?

"Abandoned Sunnahs" are those prophetic practices, whether verbal or practical, whose abandonment has become widespread among Muslims. Islam began as something strange and will return to being strange as it began. "So blessed are the strangers." Acting upon the Sunnahs in times of strangeness carries a great reward. Abandoned Sunnahs are not all of the same rank; some are emphasized, such as the regular (Rawatib) prayers and the Witr prayer. All the Sunnahs of the Prophet, peace be upon him, are required to be revived and propagated, but wisdom must be exercised in spreading them, especially if people are unaware of them, so that they may accept these practices.