Fouls and rebounds appear to me to be the biggest identifiers of high aggression but steals may also be a signal.
I've never noticed a link between fouls and steals. It's almost certain that there are several hidden attributes that contribute to different skills not just one blanket 'aggression' attribute. I don't even think there's a strong link between a player committing fouls on defense and drawing fouls on offense, I think they're in there as 2 different attributes.