The Prophet ﷺ used to say, "O Allah, I seek refuge in You from disbelief, poverty, and the punishment of the grave."
حدثنا وكيع حدثني عثمان الشحام
أن النبي ﷺ كان يقول اللهم إني أعوذ بك من الكفر والفقر وعذاب القبر
Its isnad is sahih. Uthman al-Shahham is Ibn Abdullah, deemed trustworthy, and his hadith is found in Muslim and the four [Sunan compilers]. The hadith is found in Nasai 8/267, in the chapter on seeking refuge, seeking refuge from the evil of disbelief.