Any matrimonial union would have as main goal the protection of Mary's holdings against Louis XI, . Charles de Savoie, assuming his brother still dies, would inherit a duchy that was more or less in conflict with Burgundy in the last decade, but admittedly, there wasn't much choice. It wouldn't make Mary's position that much better, tough, as Savoy didn't entierly recovered from the XVth century issues.
The King of Bohemia, Vladislaus is also a candidate..
I'm not sure it would have been the wisest choice : that Vladislas could afford a situation of quasi-bigamy (as Barbara of Brandeburg was still alive and the divorce unacknowledged) is a thing, especially as his political focus was more on the succession of Hungary, but Mary could less so in this situation.
So, possibly Charles de Savoie, but the political and dynastical gains would be...limited : it's the less poor choice avaible at this point.