Traders have flocked to Y Combinator’s Demo Days for years to get their palms on promising startups constructing cool tech. In spite of everything, the accelerator has produced a few of the greatest tech corporations on the earth, from Airbnb and Reddit to Dropbox, Zapier and Stripe.
That’s why we make it some extent to keep watch over the occasion to identify probably the most fascinating corporations from every batch. As I’ve been doing almost each quarter now that the accelerator has moved to 4 cohorts a yr, I requested almost a dozen traders which startups have been most in demand at Y Combinator’s Winter 2026 Demo Day earlier this week.
To make sure our listing included really sought-after standouts, an organization needed to be flagged as a ‘fave’ by a minimum of two completely different enterprise capital traders to make the lower.
As for valuations, I’m listening to that a minimum of a pair startups have raised funds at a $100 million price ticket, although notably, these startups are already bringing in run-rate income of $1 million or extra. Even for the much less buzzy startups not on this listing, the “default” valuation this quarter appears to be round $30 million, which traders instructed me is roughly two-fold the present seed market common.
With out additional ado, right here’s the listing:
Past Attain Labs
What it’s constructing: Deployable photo voltaic arrays for satellites.
Why it’s a favorite: The startup claims it has developed photo voltaic arrays which are the scale of a eating desk at launch, however unfold to the scale of a soccer area after they attain orbit. The founders say their system can enhance accessible energy ten-fold whereas slashing prices by 88%. Past Attain already has a flight deliberate for 2027, and says it has secured $325 million in letters of intent from main area corporations.
Techcrunch occasion
San Francisco, CA
|
October 13-15, 2026
Byteport
What it’s constructing: A ridiculously quick file switch protocol.
Why it’s a favorite: Based on Byteport’s founder Jayram Palamadai, present file switch protocols like TCP are too gradual for the AI age. That’s why he constructed DART, brief for Dynamic Accelerated Report Switch, which may apparently switch giant information at a mean of 10 occasions quicker than TCP, and even as much as 1,500 occasions quicker on “dependable connections.”
Hex Safety
What it’s constructing: Steady AI-powered safety testing instruments.
Why it’s a favorite: To battle hackers utilizing AI to launch continuous cyberattacks, Hex is constructing AI brokers that may act as penetration testers, always probing for vulnerabilities and safety gaps in corporations’ infrastructure. By automating what was as soon as a handbook course of carried out sometimes, Hex claims it will possibly stop assaults at a fraction of the price. The startup claims it has crossed run-rate income of greater than $1 million in simply eight weeks, which can be why VC traders, as one individual instructed me, “have been preventing” to spend money on the corporate.
Grazemate
What it’s constructing: Autonomous drones to herd and monitor cattle.
Why it’s a favorite: Transferring cattle on huge ranches is an costly and harmful enterprise, usually involving helicopters and motorbikes. GrazeMate’s founder, who grew up on a 6,000-head cattle station in Australia, noticed a technique to make life simpler for ranchers, so he dropped out of school the place he was pursuing a robotics diploma.
GrazeMate’s drones can routinely information cattle to completely different areas of a ranch, estimate animals’ weight, grass availability and progress, and may comply with pre-specified route plans.
GRU Area
What it’s constructing: Everlasting lunar infrastructure, beginning with a resort on the Moon.
Why it’s a favorite: “Humanity will turn into interplanetary. It’s a matter of not if, however when, and the time is now,” says GRU Area founder Skyler Chan, a current Berkeley grad who beforehand constructed software program at Tesla and labored on NASA-funded area tech.
Chan claims his startup has developed a “moon manufacturing unit” that may flip lunar soil into structural bricks, which he plans to make use of to construct a luxurious resort on the moon as a “wedge” for broader lunar infrastructure. GRU’s astronomical aspirations, together with its purpose to open the primary lunar resort by 2032, have made it one of the vital talked-about startups of this YC batch. The corporate has already secured $500 million in letters of intent, an invite to the White Home, and even a reservation from the Trump household.
Luel
What it’s constructing: A market for human-captured knowledge to coach multimodal AI.
Why it’s a favorite: Based by two UC Berkeley dropouts, Luel is constructing a knowledge market that connects AI mannequin makers with contributors who can submit “daily-life” actions, resembling ironing or patient-doctor conversations, to supply audio, video and picture knowledge. The corporate claims it’s producing ARR of almost $2 million inside six weeks, fueled by excessive demand from robotics and voice AI labs.
Pax Historical past
What it’s constructing: Another-history technique recreation powered by AI.
Why it’s a favorite: Pax Historia permits customers to rewrite historical past in a approach conventional technique video games can’t. Utilizing generative AI, the sport responds to infinite, advanced geopolitical situations, from “What if Rome by no means fell?” to “What if the USA took over Greenland?” The founders declare the sport at the moment attracts 35,000 each day customers who’ve performed almost 20 million rounds.
From Stil
What it’s constructing: Agentic AI for mental property and patent attorneys.
Why it’s a favorite: Stilta’s founders declare that patent disputes can value as much as $4 million per case, largely resulting from handbook doc assessment prices. The startup says its AI agent can search and analyze patents throughout databases and scientific literature, saving each time and authorized charges.
The corporate’s brokers are already being utilized by IP attorneys at pharmaceutical big Roche. For traders, one other enticing side is that the founders hail from Sweden — current Swedish successes like Lovable and Legora have created one thing of a “halo impact” round corporations from the area, one VC investor stated.
