If you want to find something you lost, say this three times while looking for it:
اللهم يا جامِعَ النَّاسِ لِيَومٍ لا رَيبَ فيه اِجمَعْ بَيني وبَين ضالَّتي
Allaahumma yaa jaami^an-naasi li yawmin laa rayba fiih, ijma^ baynii wa bayna Đaallatii
"Oh Allaah you are the one that gathers us on the day that has no doubt gather me with what I have lost".