Allah's Messenger (ﷺ) taught me some words to say when standing in supplication during the Witr, they were: "O Allah, guide me among those You have guided, grant me well-being among those You have granted well-being, take me into Your charge among those You have taken into Your charge, bless me in what You have given, guard me from the evil of what You have decreed, for You decree and none can decree over You. He whom You befriend is not humbled. Blessed and Exalted are You, our Rabb (Lord)."
Reported by Al-Khamsah: Authentic. Narrated by Abu Dawood (1425), an-Nasa'i (3/248), at-Tirmidhi (464), Ibn Majah (1178), and Ahmad (1/199-200).

at-Tabarani and al-Baihaqi added: "He whom You hold as enemy is not honoured." It is an authentic addition. Narrated by at-Tabarani in "Al-Kabeer" (3/73/2701) and al-Baihaqi in "Al-Kubra" (2/209).

an-Nasa'i reported through another chain of narrators, adding at its end: "May Allah the Most High send His Salat on the Prophet (praising him in the highest assemblies of the angels)." It is Weak. Narrated by an-Nasa'i (3/248), with the addition of "Muhammad" and its chain is disconnected, as stated by Al-Hafiz Ibn Hajar al-Asqalani in "At-Talkhees".