Hi there!
I had an Indigo a while back. Yes, you can use Virus A,B, and C patches on the B. I am pretty sure you can also use Ti patches that are using the classic oscillators. The extras in the patch will be ignored (For instance, the virus C includes an eq, this would be ignored if the patch is loaded on a B)
There are quite a few great patches around
I like the
Vengeance-Sound.de patches myself, even if they sound a bit dated.
Your best bet is to browse the presets and determine what you like. Most well known sound designers will place their initials in the patch name. I am partial to Howard Scarr patches myself.