Storm Druid- Druid. Controlling the weather is just too much fun.
Construct Rider- Alchemist.
Vivesectionist- Alchemist. Being a sneaky plague doctor of death is so much fun. Alternatively, it could probably work as a rogue archetype.
Winged Maurader- Alchemist. It totally changes the way the class is played and it would great to see it available for all small races.
Mooncursed- Barbarian. Getting some supernatural powers on an otherwise magicless class is really nice and shapeshifting is a fun mechanic.