#4 EC3 vs Lars Sullivan
This rivalry has already begun. On NXT this past week, Lars Sullivan attacked EC3 backstage (because 2 weeks ago, EC3 implied that Lars Sullivan attacked Aleister Black) before he could compete in his scheduled match with Raul Mendoza.
A face like EC3 is sure to want revenge. While a match between the two may seem like a bad idea due to the fact that Lars Sullivan is a little rough around the edges in the ring and EC3 works best as a heel, these two wrestlers have the ability to pull it off. EC3 using his power to try and take down another powerhouse in Lars Sullivan can be a great story in the ring (remember Roderick Strong vs Lars Sullivan last December).
This rivalry can also be beneficial for EC3 because Lars Sullivan is hated by the NXT Universe so the NXT Universe would be sure to get behind EC3 (who struggled to get the crowd behind him when fighting Velveteen Dream) as the face in this rivalry.