Avast Antivirus is free. Usually reliable, though it does have issue with some Unity games. I got rid of it in favor of Total AV. Like it REALLY didn't like 7 Days to Die. Whenever I'd run it, Avast would eat up 6-7 GB of RAM and use up 55% of the CPU. Total AV on the other hand, no such issue.
Hey! Long time no speak!
I'm somewhat of a stickler when it comes to AV software - I've tried numerous ones and the best one I've found is Kaspersky. Out of testing it pretty much detected everything thrown at it - including the all new Python based intrusions that we're now starting to see.
I did ditch Avast also because it kept detecting something as "malicious" when it was a .dll that came packaged with a game (retail) from like 2002, so I wasn't really too convinced it knew what it was really looking for.
Im not saying Defender is bad, putting other AV on top is needless at best and expanding your vulnerabilities at worst.
I only found out about f95 because my fiance downloaded some viruses from random addons in the comments for some japanese Harem game and needed help fixing her PC.
Best thing you can do is buying a drive and regularly do backups so you can rollback your machine if the need ever arises, cryptoviruses are a blight on humanity.
Also use extensions that autodelete cookies and block scripts, it wont help against viruses but does keep weird sites from messing with your browser. Adblocks are self defense at this point
If you really want a good solution without buying extra software - it's going to be to actually set up a VM and use that to unpack titles and see if they do anything suspicious. Scan it in there and check it all over before anything else. I do this whenever I download from an unknown host or supplier. If something suspicious shows up, kill the VM and restart - no harm done, only a few minutes of time lost.
If you're running Windows - it actually has the ability to install VM's right in the OS itself. "Hyper-V Manager" & "Hyper-V Quick Create" allow you to pretty much do everything you need.