The best alternatives to Inspiration Database are Transferslot, Autopsy, and BuyMySideProject. If these 3 options don't work for you, we've listed a few more alternatives below.
Over 2000 failed company submissions covering founder stories and company failure analysis. To continue helping the startup ecosystem, submit your autopsy today: https://startup-research.typeform.com/to/fOrakq
SideProjectors is a friendly marketplace to sell and buy interesting side projects from other people. If you are a developer with side projects then this would be a perfect community for you to discover what others are building.