Generative AI tools like the ones below are great for overviews, outlines and keyword search ideas. These tools are generally not ready yet for reliable searching for a number of reasons. Rely primarily on databases.
Perplexity AI is a tool for scholarly sources.
A key issue to consider is where a search tool is searching and quality vs.quantity of those sources.
Literature mapping is another way to gather citations by using graphical organizers to see and find links between research papers..