Ivermectin is an interesting one. Has been linked with very successful treatment (and some studies say prevention) of serious COVID cases in many countries (Mexico and Indonesia and possibly India IIRC) yet many authorities have either outlawed it or withdrawn it. In some countries death rates plummeted while using it then rose rapidly when it was withdrawn. It has been around for years and is generally very safe to use.Wikipedia is right up there with Facebook memes.
A good introduction to Tess Lawrie and Ivermectin.
I like John Campbell too – he seems very fair and balanced.
I can understand the rush to vaccinate and the race between big pharma companies to find a vaccine and I do applaud the huge success achieved in that area (I am no Anti Vaxxer by any means), but I do wonder if the world missed a trick or two with existing cheap anti virals.