[@Lonewolf685]: The unpaired characters are as follows:

Masters:
Kumozaki Keisuke
Cecil Lavernth
Victoria Vandive Velosi (for now)
Felix Wade (also for now)

Servants:
Faust
El Cid
Alexander Nevsky
Shuten-Doji
Diarmuid (for now)
And then there's Scathach in the works, who is purportedly going to Victoria.

Gonna assume that last comment set means Ghyslaine and Jack are pairing, so yeah.
Lemme know if I missed anyone.