Yes, we do have some general encyclopedias in our online list of databases, including Britannica Pre K-8 and Funk & Wagnalls New World Encyclopedia. We also have a resource geared toward younger students called Searchasaurus, which is on our Kids page.
In addition to these specific tools, we also have two databases that are collections of several materials, Electric Library and Gale Virtual Reference Library, that are great for research. Electric Library consolidates several journals, magazines, newspapers, and other research materials for easier access, and Gale VRL provides access to several specialized encyclopedias. You can select and search individual resources within these collections, or do a broader search that will access all the assembled materials.