Why contacts are not display in address book but available when typing number? Rummaged through a bunch of articles in search of an answer to this question, but nothing helped. I ask for your help.

Android 6, LG

The contact book displays only a part of the numbers (124 contacts from applications such as Skype, Weiber, etc.), but in fact there should be much more contacts and they are in the phone (confirmation of that - when entering phone number +7 there are 449 numbers).

How can I make these 449+ contacts appear in the contact book?

In the display settings of contacts, it is possible to display contacts from all sources (phone memory, SIM, applications). I tried the sources one by one, too.
You have 124 contacts saved to your phone. When you press +79, you get 449 in the dropdown. This 449 represents the number you have dialled (starting with +79) till date, from your device. Those may be the saved numbers or unsaved too. This is not a bug. Hope this satisfies you query. 

Update - adding the screenshots of my Lg 5.0.1.  When I search for contacts starting with 7 in Contacts tab, 250 contacts are shown.



While, when I type 7 in dialer, 396 contacts are found.


That's what happens with every phone. It's not a bug.