Easily the largest free online portal to the genealogical galaxy is Cyndi's List of Genealogy Sites on the Internet. This website has been maintained for free for nearly twenty years and the owner now wishes to upgrade the hosting platform. Please consider making a small (or large if you prefer :)) donation to assist financially with this transition and keep Cyndi's List available to all.
If it is possible that you have never been to Cyndi's List, take a trip there now and check out the seemingly endless lists of links and resources. You won't be sorry. Well, maybe you will, because you won't get anything else done today. And you will probably have to have cereal for dinner. Again.