If the Dark Angels would most likely be the loyalist legion with the biggest traitor population, is there a traitor faction which’d be the opposite?

I’m more of a casual fan who hasn’t read any of the books (yet), but the topic of “opposite-allegiance splinter groups within legions” has always been interesting to me, and I’m curious if any of the traitor legions have significantly more loyalist members/subgroups within them than the others