I use malwarebytes
but I also heard that either TOTALLYNOTAVIRUS_SPYWARE_FREE _DTECTS_ALL_AVIRUS.NOTAVIRUS. EXE and VIRUSADDEIMEANREMOVER.EXE are both very good antiviruses.
I say this because: watch out. I once was looking for an antivirus for my old iMac and I found one that had some good reviews (so I saw). Looked trustworthy so I installed it.
bad idea.
Turned out it was a really bad virus that literally forced every 2 minutes some really intense gory research to show up. it was...
bad.
Though in all seriousness, malwarebytes has been good to me.