In Chapter 44 of the Sabha Parva of Mahabharata, during the Rajasuya Yajna of Yudhishthira, Shishupala criticises Krishna using many insults, and then Krishna retorts to Shishupala's insults directed at him. He talks about how Shishupala committed many sins, and in particular lists these sins:
"This wretch of cruel deeds, ye kings, hearing that we had gone to the city of Pragjyotisha, came and burnt Dwaraka, although he is the son of my father's sister. While king Bhoja was sporting on the Raivataka hill, this one fell upon the attendants of that king and slew and led away many of them in chains to his own city. Sinful in all his purpose, this wretch, in order to obstruct the sacrifice of my father, stole the sacrificial horse of the horse-sacrifice that had been let loose under the guard of armed men."
So Shishupala, when Krsna was off battling Narakasura, had arrived at Dvaraka, manhandled one of the attendants and had burnt Dvaraka. He had also stolen the horse of Vasudeva's Ashvamedha Yajna.
While Krsna lists all of these offences, none of these incidents are found either in Mahabharata or in Srimad Bhagavatam. Though since it is Krsna himself who is speaking, his words can be taken as a truthful account. So are there any scriptures which talk about Shishupala's deeds in Dvaraka?
Also, when and how did Vasudeva conduct the Ashvamedha sacrifice, which is meant only for emperors? The only account I know of Vasudeva's Ashvamedha is during the sequence of Prabhavati-Pradyumna Parinayam, which occurs in Harivamsa. But there, no such stealing of the horse occurs. So do any other texts talk about this?