As a result of a number of recent failures, things have changed here. I’m now listing the Avira AntiVir Rescue System as number one:
and second, the venerable Trinity Rescue Kit:
TRK has five different antivirus scanners configured; of the five, F-PROT and Clam are working very well, BitDefender’s auto-download site kept stalling for me, Avast needs a license, and Vexira is not working right now.
Softpedia gives us this list for reference: