Examined WordPress Plugins

TinyMCE Advanced

It allows you to add useful buttons to the visual editor and also to improve the context menu.

It is part of the basic WordPress installation, you only need to activate it (you can set it free of charge -> set the zero amount of the gift).
It filters out the spam caused by previous robots in comments that visitors can usually leave behind each article or page. (Robots are programs that automatically visit the site and try to do some activity.)

iThemes Security

Secure and protect the web from hacker and robot attacks (malicious code). Because WordPress uses about 30% of all sites in the world, this platform is a frequent target of attacks, so every WordPress site needs effective security.
This add-on has a number of effective shields that can be intuitively customized in settings.

WP Fastest Cache

Pages in WordPress are usually loaded longer than well-written stands directly in the code. The reason is that WordPress is a publishing system that makes many script files (programs) that run on the server before loading pages and employ a server processor and RAM.
With this add-in, the pages remain pre-configured for caching without having to re-generate them with scripts, which will usually speed up the loading of the site.

Yoast SEO

Search engine optimization - it helps to write pages and articles so they can be easily found in search engines. (Google and Seznam)

AddToAny Share Buttons

Allows you to add buttons for instant sharing of content across different social networks under each website or article.

Photo Gallery by WD

One of the most widespread photogalleries. It does not contain errors like some other. It is also extensively configurable in the free version.

MetaSlider

Allows you to create sliders (changing images). It is possible to set the exchange interval and animation during the exchange.
With the additional Meta Slider Schedule Slides, it is possible to schedule displaing/hiding of pictures depending on the date and time.