Depending on what microcontroller/dev board you’re using, you may have all the IO for your project that you need. On the other hand, perhaps you want to integrate a few buttons, an LED, or small buzzer and don’t have the necessary pins available. Or maybe you just don’t have the patience and/or physical room needed to run the appropriate lines.
The good news is that you don’t actually have to run every single line if you can instead implement a protocol like I2C. The even better news, depending on your situation, is that the I2CUI4_V1 module from iotdevices integrates 5 buttons, a buzzer, and RGB LED into one convenient PCB. The device also has another 7 GPIO pins that can be broken out via pin connectors, expanding potential interface possibilities even further.
The product listing notes that this would work well in clocks, multimedia devices, weather stations, and more, but the possibilities are really only limited by your imagination. It works with both Arduino and ESP-based devices, the latter of which would make it perfect for use with Home Assistant setups, especially when it would be easier to mash a button or two rather than getting out your phone!