Spectra Pro is large Gutenberg block collection. It has support for dynamic data and custom fields and can be used in the content editor and the Full Site Editor for creating theme templates. It has a loop builder which you use for creating archive templates. It also has a popup builder.
Spectra Pro is usually paired with the Astra Pro theme which has a module for building site templates. You can also use it with the block-based Spectra One theme in the Site Editor.