When it comes to creating motion effects, such as explosions or the jet stream of an alien spaceship, Unity's particle effects are the way to go. Particle systems emit sprites or meshes, which we call particles, which then create a combined effect. Particle properties can be configured from their color and size to how long they stay onscreen and how fast they move in a given direction. These can be created as single objects or combined to create more realistic effects.
Particle system effects can be extremely complex, and they can be used to create almost anything you can imagine. However, getting good at creating realistic effects takes practice—take a look at these instructions for a place to start: https://docs.unity3d.com/Manual/ParticleSystemHowTo.html.
The pickup item is still looking a little bland, even though it's spinning. Let's add an effect to make it stand out.