Well, as an indie Dev team of 3 people, i have to put every "hat" that i could, for Magic Kitten i need to make the entire visual identity and visual elements, UI, Gameplay Assets, icons, Marketing images, etc.
This is a little example of how we ended up with some of the core design in game, first the kittens (The pieces that we use in our game) and the potions (Some extra helps for the players).
The rest of the icons in our games (Like the obstacles, power-ups, etc) are based in those first implementations.