What are the hidden-gem AI Agents everyone should know by now?

Most people only hear about the big, mainstream AI agents- the ones pushed by major platforms or hyped on social media. But there are a lot of lesser-known agents quietly doing incredible work: more autonomous, more specialized, or simply way more effective than their popularity suggests.

So I’m curious, what are the hidden-gem AI agents you think more people should know about? Would love to hear the underrated agents that deserve way more attention.