I have explained Base Attack Time in the previous post in which you know why you can't let an Anti-Mage farm. In this post, I will list the lowest BAT heroes.
#1 Alchemist (in Chemical Rage) - 1.15
Alchemist, when turn on Chemical Rage will have:
1.45 BAT at level 6 (Level 1 Chemical Rage)
1.3 BAT at level 11 (Level 2 Chemical Rage)
1.15 BAT at level 16 (Level 3 Chemical Rage)
#2 Anti-Mage - 1.45
You shouldn't let Anti-Mage farm!
#3 Lycanthrope...