Is there any special virtue in reciting the Qur'an after Maghrib prayer?

There is no evidence for the superiority of reciting the Qur'an after Maghrib over other times. Reciting the Qur'an is one of the greatest acts of worship at all times, as long as the reciter is ritually pure, and it is the best type of remembrance (dhikr).

If the intention is recitation during prayer, it has been said that "the vigil of the night" (nāshiʾat al-layl) mentioned in Surat Al-Muzzammil refers to the prayer between Maghrib and Isha, which would then have a special merit.

Reciting the Qur'an is an act of worship at all times. It is recommended to recite it during quiet times for contemplation, and these times are often at night, especially its latter part. Some scholars have explicitly stated that the night is the best time for recitation.