Do you know of any unconventional marketing strategies that worked ?

There are so many. I love the Reddit Superbowl 5 second ad - https://www.nytimes.com/2021/02/... Considering how expensive SuperBowl ad time is, taking a minimum buy and making it work is brilliant. Freshworks is known for running a "Failsforce" blimp over the SalesForce Dreamforce summit - It's what's triggered Salesforce and AWS to control ALL advertising in a 5mile radius around their major events. PayTM has a "soundbox" which loudly speaks out every successful payment - https://business.paytm.com/soundbox High-frequency merchants (think starbucks or a busy department store) love it as they don't have to check if a customer's payment has come in successfully. Customers just pay and go, without waiting to be acknowledged.