The 3 verticals where AI agents are quietly printing money for solo operators right now

Spent the year tracking which "I built an agent for X" stories on this sub and IndieHackers actually turn into revenue. Most don't. A few categories keep recurring among people who are pulling 5 figures a month solo. Sharing the pattern in case it's useful. Voice agents for local service businesses By a wide margin the highest-margin solo opportunity I've watched work this year. VAPI and Retell brought voice agent costs down to roughly 20 cents a minute. Local businesses (dental offices, HVAC, restaurants, salons) are losing 20 to 40 percent of inbound calls to voicemail every week and they have no idea this exists yet. The pattern that works: build one voice agent template for one vertical, sell it as "we make sure every call gets answered," charge 1500 setup plus 1000 to 1500 a month. Five clients gets you to 7500 MRR with maybe 4 hours of weekly maintenance. The buyer doesn't want a voice agent. They want missed calls to stop costing them revenue. The agent is invisible delivery infrastructure. Agent ops for small businesses (the "wedge" play) This one is slower to land but the upside is bigger. You walk into an existing cashflowing small business (a 10M revenue HVAC, a 5M accounting firm, a 3M law practice) and you deploy 3 to 5 small agents that handle their most expensive admin work. Inbox triage, intake automation, estimate generation, document review. The interesting part is the deal structure. The good operators in this space aren't selling retainers. They're trading delivered impact for equity, rev share, or hybrid. A 2 percent stake in a 10M business doing 25 percent margins is worth way more than a 5K retainer over time. PE firms are doing this at scale via roll-ups. Individual operators can play the same game without capital. Agent ops for content and sales at series A startups Less sexy but very repeatable. Startups doing 1 to 10M ARR are paying 100K+ a year for sales ops, content ops, customer success heads. A solo operator can come in with 5 to 8 small agents (lead enrichment, inbound qualifier, content repurposer, support triage, churn risk alerter) and replace 30 to 60 percent of that overhead for 3 to 6K a month. The agent itself takes a weekend. The relationship and the customization is what's defensible. What's interesting across all three: the agent is never the product. The product is always "outcome X happens reliably without your team having to do it." The agent is the delivery mechanism the buyer never has to think about. Curious what others are seeing land in the wild. What verticals are you watching that aren't obvious yet?