there are some OB-type main stars that are not Blue stragglers from the globular clusters in the space engine
Why they can't be Blue Stragglers? because they have planets?
For example, as we all know, the O-type main stars are more than 15 times of sun's weight but in the space engine I've found a star with merely 7 times of sun's weight as O-type main stars
I don't have time now to check but I suspect there have to be very massive O-type stars in the engine. For example, a user found this star that has more than 75 solar masses. It's not a blue star but I don't think those are limited either to non realistic masses. Maybe I'm wrong