Sunnah.com reference : Book 7, Hadith 51English translation : Book 7, Hadith 824Arabic reference : Book 7, Hadith 821
Narrated Abu Sa'id al-Khudri (RA):
The Prophet (ﷺ) forbade buying what is in the wombs of domestic animals till they give birth; selling what is in their udders; buying a runaway slave; buying (something from) the spoils of war until they are divided; buying Sadaqat before they are received; and the unknown catch (find) of a diver.

[Ibn Majah, al-Bazzar and ad-Daraqutni reported it with a weak chain of narrators].
وَعَنِ أَبِي سَعِيدٍ اَلْخُدْرِيِّ ‏- رضى الله عنه ‏- { أَنَّ اَلنَّبِيَّ ‏- صلى الله عليه وسلم ‏-نَهَى عَنْ شِرَاءِ مَا فِي بُطُونِ اَلْأَنْعَامِ حَتَّى تَضَعَ, وَعَنْ بَيْعِ مَا فِي ضُرُوعِهَا, وَعَنْ شِرَاءِ اَلْعَبْدِ وَهُوَ آبِقٌ, وَعَنْ شِرَاءِ اَلْمَغَانِمِ حَتَّى تُقْسَمَ, وَعَنْ شِرَاءِ اَلصَّدَقَاتِ حَتَّى تُقْبَضَ, وَعَنْ ضَرْبَةِ اَلْغَائِصِ }  رَوَاهُ اِبْنُ مَاجَهْ, وَالْبَزَّارُ, وَاَلدَّارَقُطْنِيُّ بِإِسْنَادٍ ضَعِيفٍ  1‏ .‏‏1 ‏- ضعيف.‏ رواه ابن ماجه ( 2196 )‏، والدارقطني ( 3 / 44 / 15 )‏.‏