This module is just the opposite as Blockfield. It converts a field into a block. For example, you can show an image of a content type somewhere in a block instead of between the other fields. This can be useful and is actually a kind of 'light' Panels or Display Suite.
The Field Group Module allows you to use tabs and accordions for your field structure, for the input and output modes. The Field Group Background module allows you to set a background, without using any CSS.
This module competes with the Bricks module for Bootstrap. A little bit less flexible, but more settings for the layout. It works with Bootstrap 4 themes like Breeze. This theme adds some nice CSS to the module.
Display suite (short DS) is very popular. It offers you the possibility to split up your content block into regions (= extra blocks). Within these regions you can put your fields en add some CSS. DS allows you to make view modes for content types, others than teaser and full mode.