Bots don't see stickers as stickers but as a link to download the sticker file. What we can do using this info is hack the AI into recognising the links and responding to the stickers your bot receives.
Getting the URL of a sticker
To get the URL of a sticker so that you can enter it in the AI Setup you can use a User Input Plugin in combination with a simple text card. You can then send a sticker to the bot and have it respond with the value of the user attribute generated in the user input plugin in the text card.
In the above case I've added these blocks in the Default answer block of my bot, now whenever I send a text or sticker the bot just responds with the input it has received.
Using the AI to respond to a sticker
We can now send as many different stickers as we like, note down the URLs, and then enter them in the AI Setup so that our bot knows what to do when it receives such a file.
And voila, we have just taught our bot bot to respond to stickers. 💪