Many/most films only have closing credits, which will start with the director/writer-director credit, but some use both opening and closing credits, often for stylistic reasons will be paid a fixed fee for their work, whereas a gaffer or set designer’s work is more flexible as a scene being cut may mean that a particular set simply doesn’t need to be built.
Of the below-the-line crew, the first and second assistant directors are always high up the credits list, but it is usually the unit production manager who gets the honour of having their name up in lights first after the film climaxes.
You might be wondering why films sometimes conclude, with a musical crescendo, to reveal the name of the Unit Production Manager(s) of all people, before the rest of the names of cast and crew involved roll up the screen.
As such, the format of its crediting system is pretty uniform.