I am going to use white for trim bands on my next build. I have never used white thread before. Is there a particular white thread that most builders use or prefer?

Whatever brand, I would use NCP.

.........

I use size A Fuji white NoCP thread for trim wraps. Very opaque with no bleed through.
Norm

I also prefer Fuji NoCP (in white) over other brands.

Rog

ditto

Likewise as do I

Rookie here...can I ask what NoCP means?

Does not need color preserver. The threads has been treated with a substance to prevent it from darkening and going translucent when rod finish epoxy is applied. In other words it maintains its original color without using Color preserver.
Norm

Thanks for the info. Looks like I will be buying some Fuji white NoCP to try.

OK. Following the string - I only use colorfast. Just what, if any, is the advantage to using thread that does require a colorfast? It isn't very much cheaper but the extra step would eat up any cost savings

Regular untreated thread when coated with epoxy finish will darken and become translucent, and many of us like this look. However, if you want the regular thread to maintain its original color (or as close as possible) then color preserver is required before finishing. Regular threads treated this way have more 'sparkle' and depth of color vs colorfast (NoCP) thread, which appears dull and flat by comparison. It all boils down to what you like.
Norm

finished wrap looks different
regular thread has more of a sparkle to it then NCP
especially in sun light

NoCP or NCP threads have an additive to prohibit the epoxy from making them transparent, ( a chalk like substance) the additive however has a dulling effect on the color brilliance.

One solution to retaining the brilliance, is to undercoat the warp area with white or silver. The undercoat can be paint or thread wrap.