The fourth book of the Aṅguttara Nikāya, the Collection of the Numbered Discourses of the Buddha, collects 783 suttas or discourses whose subject matter is centered on groups of four topics. For example, suttas are collected that speak of the four elements. The groups of four give rise to repetitions of the type A, B, A and B and not A and not B, or even, A, not A, A and not A and not A and not A and not A and not A. They are also employed using four of the five precepts, or groups of three to which a third component is added, such as belief, for example. 
Although this is a book made to be read, it is of little or no interest. Only some sutta may be interesting, although there are none that have a theme that is not intensely explained in the Saṃyutta Nikaya. 
Anecdotally, it is worth mentioning the suttas AN 4.61 where he says that "with his legitimate wealth he defends himself from the threats of such things as fire, floods, rulers, bandits or hateful heirs" and AN 4.120, which tells us that the four dangers are "fire, floods, rulers and bandits". It is not the only time that the Buddha puts the critical focus on the figure of the rulers whose functions are against all ethics, since their job is precisely to steal, kill and lie. 
On the opposite side and marked with a double asterisk (**), we find this time up to six false suttas. 
AN 4.76: In Kusinārā, the Buddha says he is sure that in his Saṅgha at least everyone has entered the stream...Ānanda himself being there. This is another sutta with a clear interpolation in defense of the attendant. 
AN 4.118: Inspirational, which is the precursor to a travel brochure in which the Buddha supposedly invites devotees to go on pilgrimage to the four most iconic sites...including where he would die. 
AN 4.127: Incredible things about the Tataghata, some of which are incredible, such as the galactic lights. 
AN 4.129: Unbelievable things about Ānanda. Yet another propaganda interpolation in favor of the wizard. 
AN 4.130: Four incredible and amazing things about a wheel-spinning monarch, in which we again interpolate propaganda in favor of the wizard, equating him to a universal monarch. 
AN 4.187: With Vassakāra, the gossiper. A strange sutta in which a brahmin tells a gossip to the Buddha, which had a bearing on the plot of the text. 
In short, an arduous and exhaustive work of research and reconstruction to make known some texts that really do not contain anything of real interest.