If you're looking for an all-purpose AI-based tool to analyze and summarize complex documents, Briefy is worth a look. The tool converts long documents into structured summaries in formats like short paragraphs, mindmaps and tables. It can handle multilingual documents, and it's got features like contextual questioning and a mobile-friendly reading interface. Briefy is available as Chrome and Safari extensions, as well as a Gmail extension, so it should be adaptable to whatever browser or service you use.
Another tool worth a look is Scholarcy, which is particularly good at summarizing academic papers. It can generate interactive summary flashcards, notes and highlighted passages. Scholarcy also can create literature matrices and generate bibliographies, which is useful for researchers and students trying to get a handle on a subject.
Last, ChatDOC has general-purpose AI-based summarization and analysis abilities. It can handle a variety of documents, and it's got other abilities like image analysis, multi-document chat and math formula analysis. A browser extension lets you upload PDFs for quick analysis and get q&a results, which is handy for quick analysis on the go.