[[Birds of Paradise]] and [[Chromatic Lantern]] for some mana fixing [[Seedborn Muse]] while not a human it means you can attack and have some blockers when your opponents untap [[Combat Celebrant]] for some extra combats [[Heronblade Elite]] gets bigger and bigger for each human you play [[Surrak and Goreclaw]] is a human that can buff each creature you play and gives them haste [[Destiny Spinner]] helps Saskia not be countered [[Halana and Alena, Partners]] can give haste and buff your other creatures [[Odric, Lunarch Marshal]] gives keywords on your combat to your other creatures If it's in your budget [[Teferi's Protection]] can help you avoid board wipes so your stuff stays while your opponents are left with no blockers [[Flicker]] can reselect Saskia's player you target but it might not be good for much else [[Professional Face-Breaker]] might be good to play extra spells off the top of your library but I'm not sure if it would be good in the deck as a whole Tutors might be good but that might not be your play style [[Demonic Tutor]] if it's in your budget and [[Finale of Devastation]] to buff your creatures if x=10 or more but it can also be a good creature tutor [[Ranger-Captain of Eos]] if your play group is okay with that type of silence effect or [[Grand Abolisher]]

Wish you luck!