Give me brief example for the following below:$1-$ Rahnu $($mortgages$)?2-$ Kafalah $($ Guarantee $)?3-$ Wakalah $($ Agency$)?4-$ Qard Hassan $($Benevolent loan$)?5-$ Hiwalah $($ Transfer of debt $)?6-$ Tabarru $($ Donation $)?7-$Hibah $($ Gift$)?8-$Ibra $($ Rebate $)?$