Yes, they're pretty standard.
The only significant exception is for Graflex reflex cameras (not Graphics in general like the Speed, Crown, Anniversary, Pacemaker, etc.), which use a wider filmholder with grooves on the sides. Also, Graflex-type holders have a groove on the face that meshes with a rib on the camera back, opposite to the way a conventional holder works. Note that Graflex made Graphic, or conventional type holders as well, so even though a filmholder says "Graflex" on it, it doesn't mean that it's a Graflex-type holder.
Another thing to watch out for is Tiltall filmholders that sometimes show up on eBay. These seem like they must have been made for some specialized equipment or they just all have a major design flaw which is the lack of a lock rib, so they aren't necessarily light tight in the film back, and there's some risk of pulling out the holder while pulling the darkslide.