Originally Posted by hypo

The elixirs can be dropped on the Standing Mission - In Search of the Blooming Elixir.
The Fururu birds can be dropped in the Concept missions. There also have been some events giving them as rewards.
The petals can be dropped on their respective Nation Deffense missions. There too, some events gave a few as rewards.

there are so many concept missions, does some in particular drop them?