One of Silicon Valley’s most storied startup accelerators, Y Combinator, held its Winter 2025 Demo Day on Wednesday, showcasing what its latest batch of 160 startups are cooking up. Some of Silicon Valley’s most successful startups — including Stripe, Airbnb, and Reddit — started out in a YC batch.
Today, YC’s newer startups are focused on building the next big thing in AI. In this batch, we noticed a surprising number of startups creating tools to enhance other companies’ AI agents. Rather than building their own AI agents, these startups are building support tools. There’s no shortage of companies building AI agent tools today, but these managed to stick out from the crowd.
There are some honorable mentions that didn’t quite make this list but still managed to catch our attention. There’s Optifye, a startup that’s building software to manage factory workers and was embroiled in a social controversy a few weeks ago. There’s also Artificial Societies, which runs AI simulations to test how well your LinkedIn posts will do in a simulated version of your network.
YC has always accepted some eye-catching companies, but here are the startups we think are worth paying attention to in YC W25.
What it does: API for agent teleoperation
Why it’s a fave: One of the key reasons Waymo has been successful at deploying autonomous robotaxis is because humans can remotely take over a vehicle if one ever gets stuck. Abundant took that same idea, teleoperation, and built a platform that applies it to all AI agents. Abundant says its API allows it to catch when an AI agent fails, and allows one of its human operators to step in and take over.
What it does: lets AI agents navigate browsers
Why it’s a fave: Coincidentally, Browser Use went viral earlier this week because a Chinese AI agent, Manus, used its open-source tool to click through site menus and fill out forms on browsers. Daily downloads quintupled to 28,000, one of the founders told TechCrunch. As web-browsing AI agents such as OpenAI’s Operator are taking off, Browser Use seems to be offering a compelling open source tool that enables them.
What it does: replaces tedious grading work with AI
Why it’s a fave: Teaching assistants (TAs) are the backbone of any modern university, quietly grading papers for professors and doing other grunt work. But grading piles of repetitive papers might not be the best use of a TA’s time when they could be directly teaching students. Founded by Cornell TAs who openly declare that they “hate grading,” GradeWiz uses AI tools to automate the task so TAs can make better use of their time.
What it does: Robinhood for Pokémon cards
What it’s a fave: Misprint has a cool origin story — its co-founder, Eva Herget, quit her job at Goldman Sachs to sell Pokémon cards full-time, raking in $40,000 a month. Now, Herget and her co-founder have launched a platform for selling cards and other collectibles that allows users to treat them more like stocks, using a bid/ask system. It’s not a small market: $3.5 billion of secondhand Pokémon cards are sold every year, Misprint says.
What it does: uses AI to find the best vibe coders
Why it’s a fave: AI-assisted “vibe coding” is all the rage, with a YC partner recently saying that a quarter of YC startups have codebases that are 95% AI-generated. But AI-assisted coding isn’t just cheating: it’s a skill in and of itself. NextByte says it helps companies find the best “vibe coders” thanks to an AI model that powers interview questions testing coders’ skills at leveraging AI.
What it does: AI clone for Zoom calls
Why it’s a fave: Who hasn’t popped into a Zoom meeting for work with a bad case of bed hair or barely concealed pajama pants? Pickle solves this by letting you “clone” an ideal version yourself and putting that much better-composed individual onto the screen, lip-syncing to your voice in real time. As a (mostly) remote team, we really hope Pickle — which says it has over 1,500 paying users so far — can pull this one off.
What it does: AI agents to automate restaurant management
Why it’s a fave: We’ve worked enough jobs waiting tables to know that managing a restaurant is not an exact science. Managing restaurant inventory is often done in Google Sheets, and involves lots of calling and emailing with suppliers. Rebolt tries to automate some of that work with AI agents, and the company says it’s in pricing discussions with the parent company of Burger King.
What it does: a Roomba for weeds on a farm
Why it’s a fave: Weeds kill farms, but removing those weeds is a difficult task that requires lots of human labor. Founded by a former Apple hardware lead, Red Barn Robotics claims its weeding robot, which it calls “The Field Hand,” is 15x faster than a human and a quarter of the price. The company has already signed $5 million in LOIs for the upcoming growing season.
What it does: a vintage clothing marketplace curated by AI
Why it’s a fave: If you’ve ever shopped for vintage clothing online, you know that it can be an overwhelming experience. There are lots of options, and it’s hard to assess quality. Retrofit uses AI to sort through thousands of vintage listings and creates a marketplace based on current trends. Plus, their website looks great.
What it does: autonomous patrol boats
Why it’s a fave: Autonomy is hot in defense tech right now, from Shield AI’s “AI fighter pilot” to Saronic’s planned autonomous warship factory. Splash builds small patrol boats that autonomously patrol sea borders. The startup says it has already cruised autonomously 200 miles in the San Francisco Bay Area and claims an impressive 800-mile range.
