The next forgotten sunnah is 12 additional rak’ahs
Also, a very important sunnah is the performance of sunan ar-rawatib.
Umm Habibah, the wife of the Prophet, peace and blessings of Allah be upon him, said: “ I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: “Any Muslim who performs every day in addition to the obligatory twelve rak’ats voluntary prayer, Allah will (certainly) build a house in Paradise .
Muslim 1/503, No. 728.
12 rak’ats are:
2 rak’ats before fajr,
4 rak’ats before zuhr,
2 rak’ats after zuhr,
2 rak’ats after maghrib,
2 rak’ats after ‘ish.
If you constantly commit them, Allah will surely build you a house in Paradise.