With the unblockable maybeboard, a card I personally find underrated and unexpected is
Outmaneuver .
Also your infect creatures are usually rather small when you don´t have
Mirror Entity on the field. So they will find themselves in the graveyard pretty quick, so maybe you should add a way to help them out of there. Getting back a
Phyrexian Swarmlord or
Hand of the Praetors lategame is worth
pure gold sometimes.
But the Saskia-Infect combo is pretty neat, when one player has an opening you get to kill another one for free!
What about
Blade of Selves ? creates many problems if there are 4
Blightsteel Colossus attacking everyone.
Proliferate is difficult as it is one way to add poison to your enemies instead of making them unblockable. I think a focus on one of those strategies would benefit you more than both at the same time.
Have a nice day!