I have bought BrainPad Arcade and it is fun to play with.
But is there any possibility to import my own sprites or tiles.
Hi, @Zoki. Welcome!
The short answer to this is “no.”
The longer answer: You can build your own sprite packs, although I have not yet tried this myself. https://github.com/microsoft/pxt-arcade/blob/master/README.md (Scroll down a bit for the information on creating a sprite pack.)
Thanks for the answer.