In Islamic law, free gift of nature not owned by anybody or anything which is free to be used by public.
Mudarabah al muttaqah (unrestricted mudarabah)
Iman bil gha'ib
CLCs (Central Lending Certificates)
Ibra’
Dhawu al-arham
Al-‘ushr
Musharakah Mutanaqisah
Al-muslam ‘ilaih
Riba al-nasi'ah
Rukn