If you dont mill them in one go, two activations should be more than enough
Create your Rat biker gang with heavy-duty ships to crew, such as High-Speed Hoverbike , Smugglers Copter , Surgehacker Mech , Necron Monolith , and even the Vehicle mothership that is Parhelion II
Though it's possible for your opponents to outdraw you through this effect, the fact you can get two draws every turn keeps things in your favor
For example, if you engage with a 3/3 without first strike, it'll be a 1/1 when you take damage back and you'll survive
Abhorrent Oculus Abhorrent Oculus can be a 5/5 flying creature and a 2/2 manifested creature, and you get a new 2/2 every turn
Rushing River (Invasion/Planeshift/Apocalypse) Why bounce just one creature when you can bounce a second for the cost of a land