1. Merlin

Website: https://merlin.foyer.work

Pros: Merlin is the most popular extension for ChatGPT users, boasting over 700k installs. Its rich functionality covers aspects such as YouTube summarization, blog post summarization, Gmail integration, and even social network support. It's an all-in-one solution to improve your ChatGPT experience.

Cons: Unfortunately, Merlin has a few drawbacks. Its user interface isn't very appealing, and it can be quite intrusive. Some users have also reported that the integration with social networks isn't always seamless, which may lead to difficulties when trying to use this feature.

2. Monica.im

Website: https://monica.im

Pros: Monica.im is another well-designed Chrome extension for ChatGPT users with over 600k installs. It offers excellent functionality, such as quick actions and image support. The fast response time and sleek appearance make it an attractive choice for those seeking ease of use.

Cons: Despite its appeal, Monica.im has some downsides. Privacy concerns arise since the author of the extension is unknown. Furthermore, the interface can feel bloated due to an overwhelming number of features, giving the impression that there's a lack of direction in its design.

3. WritingMate.ai

Website: https://writingmate.ai

Pros: WritingMate.ai is a simple, lightweight extension created by Artem Vysotsky, a professional software engineer from Meta. It offers a basic chat feature with a sleek user interface. If you're looking for something less complex, WritingMate.ai could be the perfect fit.

Cons: While WritingMate.ai delivers simplicity and ease of use, it's not as popular as the other extensions mentioned. Additionally, it doesn't offer the rich integrations some users may find useful in their ChatGPT interactions.

In conclusion, these hidden-gem Chrome extensions can significantly enhance your ChatGPT experience. Whether you're looking for an all-in-one solution like Merlin, a well-designed platform with quick functionality like Monica.im, or a simple and lightweight chat interface like WritingMate.ai, you'll find something that suits your needs. Give them a try and see which one works best for you!