Autonomous AI agent marketplaces are platforms where prebuilt, configurable or custom agentic workflows (task-specific LLM agents, multi-agent orchestrations, and plug‑in bundles) are discovered, purchased, deployed, and monitored. By 2026 these marketplaces span open-source ecosystems, cloud vendor stores, blockchain‑enabled catalogs, and enterprise catalogs that emphasize governance and observability. That makes them central to how teams adopt agentic automation safely and at scale. This topic covers marketplace types and the tools that populate them: developer‑first frameworks such as LangChain that standardize agent interfaces and deployment; enterprise orchestration platforms like Kore.ai and IBM watsonx Assistant that focus on no‑code/low‑code building, observability and governance; productivity‑integrated assistants (Microsoft 365 Copilot) and in‑IDE copilots (JetBrains AI Assistant, Windsurf) that embed agents into workflows; model and infra providers (Cohere) offering private, customizable LLMs; and service hybrids (Crescendo.ai) combining agentic AI with human oversight for guaranteed outcomes. Key trends to evaluate in 2026 include multi‑model support and model portability, agent observability and audit trails, role‑based governance and compliance features, marketplace interoperability (APIs, standards), developer tooling and SDKs for testing and safety, and hybrid human+agent resolution models. Buyers should weigh open‑source flexibility vs. managed governance, integration with existing apps and data, pricing models, and support for private models and secure retrieval. Comparing NEAR AI, Anthropic, OpenAI and other marketplace hosts requires looking beyond placement and into lifecycle features: deployment pipelines, monitoring, access controls, and how marketplaces surface trustworthy, composable agents for production use.