Milan Dinić

<a href="https://milandinic.com/wordpress/plugins/clean-expired-transients/" rel="nofollow ugc">Plugin homepage</a> | <a href="https://milandinic.com/" rel="nofollow ugc">Plugin author</a> | <a href="https://milandinic.com/donate/" rel="nofollow ugc">Donate</a>
This plugin cleans every transient from database older than one minute using safe native WordPress function. It works on multisite too.
By default, it will check for expired transients once daily, though you can call it any time using <code>Clean_Expired_Transients::clean();</code>.
Clean Expired Transients is a very lightweight, it has no settings, just activate it and it works immediately.
Note that it can be used by developers in their project in any place, it doesn’t require activation and it’s safe to use since it checks is there existing installation, just include it.
And it’s on <a href="https://github.com/dimadin/clean-expired-transients" rel="nofollow ugc">GitHub</a>.

Clean Expired Transients

Safest and simplest transients garbage collector.

minkapi

Logging in as admin, you can clear all transients from the dashboard. 
If you can find no change in your screen, it is convenient to immediately check whether it is due to a transient or a bug.

Clear Transient From Dashboard

An excellent plugin to clear out transients. Rather useful for debugging issues on your site.

Work as Stated

Logging in as admin, you can clear all transients from the dashboard.

Clean Expired Transients vs Clear Transient From Dashboard