Question: Looking for a productivity tool that integrates with multiple search engines and offers a free plan with a decent query limit.

If you need a productivity tool that taps into multiple search engines and has a free tier with a reasonable query limit, Merlin is worth a look. Merlin is a general-purpose AI chat tool that can help you with lots of things on any website. It's got research, document generation and summarization abilities. It taps into multiple search engines, and its free tier lets you make 102 queries per day. Paid tiers let you go beyond that and add other features.

Another good option is Quivr, an open-source personal productivity assistant. Quivr offers a single search engine for documents, tools and databases, and can interface with lots of file formats and other apps. It employs sophisticated AI technology and has several pricing levels, including a free tier, so you can get a lot of features and query limits.

If you want an AI-powered search engine that taps into multiple productivity apps, Klu is a good option. Klu offers unified search across Google Drive, Gmail, Google Calendar, Slack and Notion, and can span multiple accounts. It offers AI-powered answers, chat with data and smart search, and has a free trial and several pricing tiers.

Findr is another AI-powered search assistant that can extract information from multiple apps like Gmail, Slack, Jira and Google Drive. It offers immediate answers through AI-powered chat and multi-account support, with a Pro plan that offers unlimited universal search and chat with results, and a Team plan that adds more features and integrations. Findr has a strong security focus with encryption and secure infrastructure, so if you're concerned about that sort of thing, it's a good option for productivity.