__utmaUsed by Google Analytics to stores the amount of visits (for each visitor), the time of the first visit, the previous visit, and the current visit
__utmbUsed by Google Analytics to check approximately how fast people leave: when a visit starts, and approximately ends
__utmtUsed by Google Analytics to indicates the type of request, which is one of: event, transaction, item, or custom variable. If this value is not present in the GIF request, the request is typed as page.
__utmzUsed by Google Analytics to identify users by a unique number called “Client ID.”
_gaUsed by Google Analytics to records whether the visitor came from a search engine (and if so, the search keyword used), a link, or from no previous page (e.g. a bookmark).
_gat_UA-These cookies allow us to count user visits and traffic sources so that we can measure and improve the site performance using Google Analytic services.
_gidUsed by Google Analytics to store Session ID and distinguish users.
_ym_isadUsed by Yandex Metrica for ad blocker presence.
_ym_uidUsed by Yandex Metrica for user ID.
_ym_visorcUsed by Yandex Metrica for Yandex.Webvisor ID.