According to Ravensburger, "as long as the actual cost of the character is five or less, Just in Time will make the card free to play"
The reprinted cards are described as being collectibles, rather than designed for use in matches, with all of the cards being non-legal in tournaments
Enlightened Tutor Tutors like Enlightened Tutor are going to be on this list a lot because of the ratio of their cost to speed to value
Murderous Rider The current playing field for standard offers a couple of cheap options if you want to incorporate rotting flesh and zombification into your repertoire
Hugo Kupka (Bruse Tarl, Boorish Herder) Rating: 7/10 Immediately granting double strike and lifelink is already a powerful ability, but you then get to keep doing this each turn you attack with Bruse Tarl, Boorish Herder
While I dont think that its actually the strongest of the cycle, I consider it to be the most generally useful