What do you think are the most convenient solutions for working with multiple accounts on the same sites in parallel?

Question

Google Chrome

On duty, there was a need to work not only with your accounts in social networks (as well as in Google and Yandex mail, which in turn denote not only mail, but also many other seovis like Google+, Google Analytics, Yandex Direct, etc. - did not begin to prescribe this in the title of the question purely for brevity). At the same time, I would like to avoid constant re-login, insure myself against forgetting to do this (and accidentally post something from the wrong account), and be able to conveniently work with more than two profiles. Please tell us how you do it if you have faced such tasks.
UPDATE: In fact, I need not only social networks, but incl. and very little known sites. In general, the ideal solution for me is seen as follows: one browser, two adjacent tabs - two copies of the same site with different cookies / sessions / localstorage, it is desirable to tint the tabs with different colors so as not to be confused.

Answer 1

Google, as it were, supports the possibility of simultaneous authorization in several accounts. My work and home gmail accounts are open all the time.
I'm not sure about Yandex, but it seems that they had something similar.

Answer 2

Google Chrome "out of the box" allows you to create multiple independent profiles.

Answer 3

I use a maximum of two different "characters" at the same time. For such a scenario, a browser window in Incognito/Privacy Mode is sufficient. In order not to get confused, I place this window on the second monitor.
MultiFox is an extension that allows you to work with a large number of different accounts at the same time.