Dumeril's Boa- Very docile, but not overly active. They can get pretty thick too....my male is already over 6' and almost 10 lbs.

Carpet Python- Quite active, generally pretty docile and come in several subspecies.

Rainbow Boa- Beautiful, fairly docile, but shy and difficult to maintain proper husbandry.

Hog Island or other Insular Boa- Typical docile BCI personalities in a smaller package.