The best antivirus is ESET NOD32, but it is fee based. Even then Malarebytes can detect something. If you have Avira + Malwarebytes, you can be sure, you have the best free one solution. If you wanna the top, then ESET NOD32 is the only choice. There is also Malwarebytes Antirootkit soft, which is free one. You can install it also, together with Avira and Malwarebytes. If you like Linux - then Qubes OS would be top choice.