I'd love to see Flux crowdfund!
Flux's mission is to rid the world of paper receipts! They currently integrate with Monzo, Starling and Barclays Launchpad to bring a digital, itemised receipt into your banking app. As well as making progress with the banks, they have also integrated with a few large retailers, for example KFC and Papa Johns (Costa is coming soon).
I see it as a great crowdfunding opportunity because there is still a lot of progress to go in terms of the number of banks they need to integrate and getting retailers on board. Plus, I think the power of the crowd being invested will help encourage banks/retailers.
They raised a Series A from VCs in December 2018, however for their next funding round it looks like they are strongly considering crowdfunding. This is from their website FAQs: