Heading & Paragraphs are the two text blocks in TheDock. The two blocks share most settings, but Headings can be any heading-tag in the markup, while Paragraph is always a paragraph-tag.
Image & Gallery are two blocks that feature images as their source. For single Images the source can be anything from a WordPress field, to the WordPress Media library or Unsplash. Gallerier require a WordPress gallery or a ACF Gallery-field.
Buttons, Icons and Separators are important blocks in TheDock, each with their specific settings. Both Buttons and Icons can include iconography though, with some difference in sizing, positioning and so forth. Separators are very useful in creating varied layouts.
Lists are ul- or ol-tags with items listed in regular fashion. Lists have multiple styles and can use multiple columns. Quotes are blockquote-tags intended for quotes or text highlights but the block can be used to create a more flexible text layout in many different ways.