Everything shown on an electronic navigational chart (ENC) is called an object, and each object has a set of attributes that describe its details. The concept is discussed in this article about ENC terminology.
Our textbook Introduction to Electronic Chart Navigation has a list of all ENC objects and all attributes, but it does not include all the possible values of each of the attributes for all of the objects. This would be many pages of fine print. We have an example online that shows the complexity: Landmarks in ENC. Looking at that we cannot help but say, "We need an app for that, " and indeed there are online resources that do just that. They are called, reasonably enough, ENC Object Catalogs.
Note added Dec 6, 2023: as of today this link to s-57.com does not work. It has been there for 10 or 15 years. We will wait a week or so, to see if it comes back, and if not rewrite this article with examples from the Caris site linked below. In the meantime, the description applies essentially to both.
An easy one to remember is this resource from Russia:
The name comes from the IHO standard for ENC content, called IHO Transfer Standard For Digital Hydrographic Data, Edition 3.1, Special Publication No. 57, usually referred to as simply "S-57." This is a complex document that refers to what should be in the ENC—it does not, however, specify how the information should be displayed on our screens. The rules for the display are in another complex document called S-52.
The landing page of s-57.com looks like this: