Not all edge connector accessories will be robotics related. There are also accessories such as mini pianos that support touch so it feels like you’re playing a mini piano!
There are a few different accessories that let you power the Brainpad using a battery while also providing a different grip to how you hold it. Most come with a thumb stick which could be more practical for your genius ideas.
Breakout boards break out the pins that the Brainpad offers and labels the pins you can use on the board. These type of boards will be crucial to makers as it allows you to wire electronics to the Brainpad such as a LED