Along with the Generation 7 Sprite Pack (Link Below), these sprites are absolutely fantastic for giving your game a consistent Generation 4 art style. Please note that the file structure in Pokemon Essentials since version 19 has changed. To install on newer versions, first save the included folders in your project's root directory. Then in the debug menu under "Other Options...", run the Rename Old Sprites script.
https://reliccastle.com/resources/470/