There's also a new card for research topics. Google tries to find in your search history a list of related queries. If you've been researching a topic, it's likely that you've tried different versions of a query and you've clicked many search results. Google Now shows a card with other useful pages from the same topic. It's interesting to notice that Google can find the name of the topic and shows a page that groups results for various queries. Google also includes a "history" section with pages you've already visited.
For some reason, the pages generated by Google return an error messages if you try to open them using a desktop browser. You need to change the user-agent to open pages with URLs like https://www.google.com/now/topics/t/LONGID.
"The research topics card appears when your recent Web History includes several searches related to a single topic – such as a trip you're planning – and Google detects relevant webpages that you may not have found yet. For this card to appear, you must have Web History turned on for the account you use with Google Now. To explore more links that may be relevant to the topic, touch Explore at the bottom of the card. From the list of links, touch the History tab to view a summary of your recent Web History related to this topic," informs Google.