What dua should you read if you you have lost ssomething and are looking for it?

Recite: اللَّهُمَّ رَادَّ الضَّالَّةِ وَهَادِي الضَّالَّةِ أَنْتَ تَهْدِي مِنَ الضَّلَالَةِ ارْدُدْ عَلَيَّ ضَالَّتِي بِقُدْرَتِكَ وَسُلْطَانِكَ فَإِنَّهَا مِنْ عَطَائِكَ وَفَضْلِكَ

"O Allah, the One who returns the lost, by Your power and awe return what I have lost, for surely I have received it as Your gift and favour (boon)".

(Hisnul Hasin)

Here is the du’aa to help you find something that you’ve lost. It has been very helpful to me. It can be difficult to locate on the net so I’m posting it here.

Allahuma rabb al-daula, haadi al-daula

Oh Allah, Lord of what is lost, Guard of what is lost

Anta tahadi min al-daula

You Guide from the lost

Agree with Baba Ali bro,but in addition to this we should offer 2 Rakats of hajat and after that we have to pray to Almighty Allah to provide the lost thing back.. Fi-Amaanillah..

 Let me add that which also stands tried, with Allah's grace; it is to keep reciting 'Innalillahe wa inna alaiherajeoon'. Either you find your lost thing with Allah's will or Allah may give you a better replacement.