I know one hadeeth:
I said to Ibn 'Abbas: 'Can a person, who killed a believer intentionally, repent?'
He said: 'No.'
I recited the Verse from Al-Furqan to him:
'And those who invoke not any other ilah (god) along with Allah, or kill such person as Allah has forbidden, except by right,'
He said: 'This Verse was revealed in Makkah and was abrogated by a Verse that was revealed in Al-Madinah: 'And whoever kills a believer
intentionally, his recompense is Hell.'
Grade : Sahih (Darussalam)
Reference : Sunan an-Nasa'i 4001
In-book reference : Book 37, Hadith 36
English translation : Vol. 5, Book 37, Hadith 4006
The ayah that "claimed" as abrogated is: https://quran.com/25/68-70
Hadeeth only mentions 68th ayah, but ayah 70th shows a way out (chapter 25) so I included all.
The ayah which "abrogates" above: https://quran.com/4/93
Finally, Ibn Kathir on his "Quran Tafsir" has some views on the subject definitely worthy of mention:
Ibn 'Abbas held the view that the repentance of one who intentionally
murders a believer, will not be accepted. Al-Bukhari recorded that Ibn
Jubayr said, "The people of knowledge of Al-Kufah differed on this
subject, I traveled to Ibn 'Abbas to ask him about it. He said, 'This
(And whoever kills a believer intentionally, his recompense is Hell)
was the last revealed on this subject and nothing abrogated it. Muslim
and An-Nasa'i also recorded it. However, the majority of scholars of
the earlier and later generations said that the killer's repentance
can be accepted. If he repents, and goes back to Allah humbly,
submissively, and performing righteous deeds, then Allah will change
his evil deeds into good deeds and compensate the deceased for his
loss by rewarding him for his suffering.
Disclaimer: these all public information, I do not deny or support any of views here. I gave references and links, as always do you own research and verification on the subject.