Cliffordcooley has given a good list.
I have used all of the others, at various times over the last 8-10 years.
I would add just one to it... which is a paid AV solution.
Some do not like it for that reason.
Others do not like it because of
how they handled one of the icons of anti-malware,
but that is a whole other story.
The one I would add is
Trend-Micro.
which has been serving me very well for a couple of years now.
I got it on a usb stick, with 5 licenses, for a great price, and upgrade/updates forever.
That, to me, makes it next to free!
Currently they are offering 3 licenses, and up to two years of updates.
And they do offer a
free trial.
.
OH... If I were you, I would also supplement your AV with
MBAM!