Pilgrim geese are gentle and easy to sex at hatch because they are sex-linked, ganders white and geese are gray. Sebastopol are also very gentle but harder to keep clean. American Buffs are striking and are generally gentle but can be more flighty than the previous two breeds I mentioned, they also come in blue and lavender. Holderread's waterfowl farm have blue and lavender and sell adults in the fall, they no longer ship goslings.
I have exhibition Gray Toulouse and they are very gentle but difficult to breed due to their size and conformation and I do not recommend them to the novice.
Blessings,
Bo