The best prayer after fard is the night prayer and the best fasting after Ramadan is fasting in the month Muharram
he attributed this to the Prophet ﷺ: He was asked which prayer is best after the obligatory prayers and which fasting is best after the month of Ramadan? He said: (1) The best prayer after the obligatory prayers is the one offered in the middle of the night, and (2) the best fast after the month of Ramadan is the fast in the Month of Allah: al-Muharram.
سُئِلَ أَىُّ الصَّلاَةِ أَفْضَلُ بَعْدَ الْمَكْتُوبَةِ وَأَىُّ الصِّيَامِ أَفْضَلُ بَعْدَ شَهْرِ رَمَضَانَ فَقَالَ أَفْضَلُ الصَّلاَةِ بَعْدَ الصَّلاَةِ الْمَكْتُوبَةِ الصَّلاَةُ فِي جَوْفِ اللَّيْلِ وَأَفْضَلُ الصِّيَامِ بَعْدَ شَهْرِ رَمَضَانَ صِيَامُ شَهْرِ اللَّهِ الْمُحَرَّمِ