Deleting a plugin deletes all its code, but doesn’t necessarily delete data it’s added to the database, or additional tables it may have created. Whether a plugin can or does delete its own data depends entirely on the plugin.
In my experience, the vast majority do not, and those that do usually have a setting along the lines if “Delete data on uninstall” that would need to be checked first.
There actually really isn’t a simple way to find this data yourself. In terms of finding additional tables, you can cross reference this list of core WordPress tables with what you have. Any additional tables would be added by plugins. There’s no precise way to tell which plugins created which tables, you’d just need to look at the name and infer it. Most will prefix with something unique. WooCommerce tables include woocommerce_, for example. But as with other plugins, WooCommerce also adds data to core WordPress tables, like posts, meta and options.
There are plugins out there that claim to help with this, but I haven’t tried any myself. From what I’ve seen many will require you to confirm if something is actually unused, because there really isn’t any clean way for a user or other plugin to tell where the data came from.