Events documentation for Craft 3 I've been looking for an Event Reference doc for Craft 3 just like what we had for Craft 2, but couldn't find one. The only events doc I found for Craft 3 is the plugin updating guide: https://docs.craftcms.com/v3/extend/updating-plugins.html#events.

Did I miss anything? Appreciate if someone can post a link here.

Also, for Craft 2 events, we used to be able to do $event->params[$paramName] to get the params passed into the events, but I struggle to find a way to do similar things in Craft 3. Any suggestions?
Whilst Doug's answer is useful for knowing the ins and outs of a particular event once you've found it, actually finding which events are available in Craft 3 in the current docs is not straight-forward. After a bit of digging, you'll find that most events are part of Craft's services - so head to the Class Reference and choose the most relevant service from the craft/services menu. The events available to each service are listed at the end. For example: https://docs.craftcms.com/api/v3/craft-services-users.html#events