Hey, my name is Kyle Corbitt and I’m a software developer at Y Combinator. I spend most of my time creating software to support our founders as they build their businesses. Before joining YC I ran my own startup.

When I was in high school, I sometimes got the frustrating feeling that all of the good startup ideas had been taken before I had a chance to work on them myself. As I’ve gotten a bit older and gained more experience, I’ve found that valuable startup ideas aren’t actually a scarce resource. In fact, they’re only becoming more abundant — as the world moves faster and more new businesses are created, more novel niches appear for profitable, productive companies.

With that in mind, we asked YC alumni and staff for startup ideas that they wish existed but aren’t currently working on.

Interested in pursuing one of these ideas? Please get in touch at kyle@ycombinator.com — I’d love to chat about your plans, and I may be able to put you in touch with the idea’s author or other good resources. Also, if you have your own great idea that you’d like to see in a future version of this list, let me know! If we see community interest we’re thinking about creating a larger repository for ideas like these.

[Edit: Since publishing, I’ve received hundreds of email responses. I’m so excited by the enthusiastic response — I think there’s really something worth building here! However, due to time constraints I won’t be able to continue responding to most of the emails I get or putting people in contact with the idea authors. If you want to reach out anyway, please include “13 Startups” in the subject line.]

AI for Communicating with Dogs

Use the immense amount of video footage captures of interactions with dogs to predict what behaviors will happen based on what the dog is doing i.e. predict that your dog is in pain, or hungry or thirsty etc. (Note: this might sound a little crazy but this has been done already for identifying pain in sheep.)

Elizabeth Iorns, Science Exchange S11

Smart Bathroom

Healthcare in the U.S. is a $3.2 trillion industry. Individuals take care of most of their health needs in the bathroom (bms, urine, teeth, hygiene, et cetera). All this data is literally flushed down the drain. Big opportunity to install a virtual doctor’s office in everyone’s bathroom, collecting data and providing feedback to help people reduce cost on health and wellness while achieving much better outcomes. New types of sensors and great data analysis and UX is needed to make the smart bathrooms a reality.

Breck Yunits, NudgePad S09

Accounts Receivables as a Service

It can be a huge pain to get enterprises to pay their vendors, even after contracts are signed. It’s one of those business inefficiencies that they’re not inclined to fix because there’s little downside to them paying late. Handing it off to a “collections agency” seems aggressive and most startups won’t do it, but I think something like an outsourced AR service that appears to be from the company but is actually a third party could be great. Potentially a mix of $/mo+% of revenue or $/mo depending at different tiers depending on how many transactions.

Yuri Sagalov, AeroFS S10/Y Combinator

Baby Bidet

A semi-automatic baby bidet where you could sit them over the sink and clean out the yuck simply and without having to touch it. Could work well as a kickstarter.

Jeffrey Engler, Wright Electric W17

Securitized Assets on the Blockchain

I would be working on making it easier to securitize and create a market for unique assets on the blockchain. There are many types of new securities and types of assets being created, not only tokens but anything else that can be bought or sold. In theory you could sell those on the blockchain currently, but you’d have to spin up and create your own blockchain in its entirety. It seems like that’s something you should be able to do as a service; I have some asset and I’d like a blockchain for it, and I’ll pay a monthly fee. I’d build that if I had time.

Austen Allred, Lambda School S17

Renewable Energy from Engineered Microbes

Microbes are outstandingly powerful and have the potential to be engineered to do almost anything. If I had more time, I would love to look more into the idea of engineering a bacteria that could efficiently convert a renewable resource into a usable fuel. Obviously, many microbes already exist that can do this, and so I would like to do more research into why this is not an option in common practice yet, and what strategies could be developed to make it possible here and now. Is the problem that the fuels they are making are incompatible with our current infrastructure (e.g. the microbes make ethanol, and most cars run on gas)? Or is the problem that bugs that can make usable fuel do so inefficiently, and thus need to be engineered to produce sufficient quantities in a cost-effective manner and/or on a reasonable time scale? In short, what problem(s) need to be solved to utilize microbes as fuel sources?

Zack Abbott, Z-Biotics Fellowship

Adwords for Outdoor and Transit Advertising

Billboards are still sold manually by sales teams. You literally cannot buy a billboard online. If people could buy them as easily as you buy an Adwords ad, maybe many more small companies would.

Jared Friedman, Scribd S06/Y Combinator

Design on Demand

Upload a photo of furniture of a piece of home decor, and select between “find” or “match” options. The “find” option would bring up very similar options and let you sort by price point and delivery time, so you could find the Crate and Barrel knock off of that designer table you saw in a magazine. The “match” option would recommends items that go well stylistically with that item. All of that instantly delivered through an app or website.

Kathryn Minshew, The Muse W12

Low-Friction Lending Library

Most people end up accumulating dozens or hundreds of items that they only need a few times a year. In my case these are things like camping equipment, a soldering iron, an electric drill, paper cutter, etc. — but everybody has their own unique list. I’d much rather not have to keep track of all this infrequently-used inventory and instead rent it on demand, especially since I have limited storage space. Lending libraries for this type of stuff exist but are too high-friction to be popular today — it’s substantially easier to just buy something on Amazon than rent it from a local depot. I think with automated inventory management and (potentially) sidewalk delivery bots the cost and friction can be brought low enough to turn this into a popular and defensible subscription business.

Kyle Corbitt, Y Combinator

Make Technology Relatable and Accessible

Technology is advancing at a rapid pace and it can be overwhelming and scary for people that don’t understand the underlying principles or have a safe place to ask questions and be taught. Think about how frustrated you get trying to explain to your grandfather why Facebook isn’t working when the Wi-Fi isn’t connected and what wi-fi is or browsers are. This is most pronounced with seniors but applies also to lots of people that don’t work in tech. It is only getting worse with topics like AI and cryptocurrency. Build a service that makes technology accessible and not scary for older or non tech savvy people. We need a text/call and software based solution with really great people on the other end who don’t judge, but explain concepts simply — someone who will help and doesn’t make anyone feel dumb. Ultimately the goal would be to make people of all types more technologically conversant while build ing a membership and/or e-commerce business model.

Avni Patel Thompson, Poppy W16

Buyer’s Remorse Insurance

Money back guarantee for art buyers: Buying fine art has a steep learning curve. Firstly, galleries are very uninviting. Then, when you get inside, the sales process is super unclear. A final barrier is that art is very arbitrarily priced, and as a new buyer it’s hard to know if you will get buyer’s remorse and feel like you overpaid for something. To overcome this, offer insurance that galleries can offer to buy art back from the purchaser if the purchaser is unsatisfied. Lowered risk for buyers => Increased spend, and you take some of that increased revenue.

Justin Kan, Justin.TV/Twitch W07

Social Network for Children

This is a super tough nut to crack. You have to be cool and offer a safe and private environment for kids to communicate with each other while enabling trusted adults to peer in/interact, etc… The company that can build something that is used and useful for all parties can build something of great value throughout a person’s entire life.

Holly Liu, Kabam/Y Combinator

Modern Firefighting

Climate change is already having real consequences on our society, and this year has been one of the worst years for wildfire in history, leaving entire neighborhoods flattened. Fire fighting and the tools we use to fight fires haven’t changed much in 100 years. Sprinklers were a big innovation for homes, but forest fires are often spotted and fought in the same way we did many decades ago. With the arrival of autonomous drones, industrial drones, better sensors and better prediction we should be able do a better job saving our forests, cities and firefighters.

Gustaf Alstromer, Y Combinator