Check the crowdfunding platform such as kickstarter, idiegogo, etc...
autopsy.io is a startup that attempted to do this. The latest update is from late 2015. I suspect autopsy.io will soon have a metaphysical problem to solve. Pity.
Product Hunt has a RIP tag. It can save you from an hour of fruitless googling.
Deadpool is more useful because the data is so current, albeit not without potential bias.
Or use this search string in google: my startup failed site:medium.com. The 3,840 results would be a goldmine for text analysis. And more.
I discourage strategy/founder coaching clients from reading this stuff. No big secrets to reveal about why--just practical ones. First, startups are hard. Focusing on what is working (or not) in your own startup pays greater dividends than learning what didn't work in someone else's.
Yes, there's an argument to be made for using these stories as inspiration. Brainstorming. Data. In the world where I ask what steps a founder took to address a growth block, though, those 3 hours were procrastination. And that's the second reason. Procrastinate if you need to but do something uplifting. Don't read about people who failed to climb the cliff you're hanging onto for survival. Whhhyyyy?
As for mining the deadpool for startup ideas, I wouldn't do it. Starting with potential customers or clients always seems to work out better. (Opinion, no data.)