hi there,
I have 4 breeds of bantam and only I large breed because I love bantams so much

I have Barbu d'Anvers , Pekin (Cochin) bantams, Coronation Sussex bantams and Silkie Bantams.
Barbu d'Anver roosters are sometimes aggressive , I don't really mind this because they are so small they cant even get to your knee.
But I decided I would just tell you so you know.
The Barbu d'Anver hens are very friendly
The hens are not great layers.
they lay about 4 cream coloured eggs a week
but Barbu d'Anvers are very good flyers so keep that in mind.
Pekin (Cochin) bantams are probably one of the most friendly bantams you can get.
the roosters are usually not aggressive and the hens are like dogs , they love to be rubbed.
They are again a layer of small cream coloured eggs
I get about 4 eggs a week per hen.
They are also great mothers
Coronation Sussex are just like Light Sussex but they just a different colour around their neck.
instead of having black they have a lavender/Grey colour.
They are very friendly birds both hens and roosters.
they lay around 5-6 small cream coloured eggs a week.
The Silkie is probably one of the most common chicken kept for pets.
They can not fly because they have no barbs in their feathers which gives them a silk look hence the name.
they lay about 3-4 small cream coloured eggs a week.
Silkies are great mothers , I even have some that adopted chicks when they were broody of course.
I have no experience with Serama's but maybe someone else can help with that.
good luck
fionn.