1. Balarama had originally planned to marry Subhadra to Duryodhan. But Subhadra wanted to marry Arjun so she ran away
2. Lord Krishna actually had two sisters Subhadra, and the other one was named Ekanaga who was born from Nanda and Yashoda.
3. Sahadev (Panadava brother), who was able to see the future, knew all about the war and circumstances, but kept it secret as he was cursed to die if he disclosed it.
4. Ekalavya was actually Krishna’s cousin. He was the son of Devashrava (brother of Vasudeva) who got lost in the forest and was found by a Nishada Hiranyadhanu. Ekalavya died protecting his father during Rukmini Swayamvar. He was killed by Lord Krishna.
5. King Parikshit’s (son of abhimanyu) wife Madravati was actually a frog!