Most of the time, it would consist of a graphic element that relates to the title itself, such as:
Sometimes, things got more ambitious. This one, for example, is part of an animated clip in which the eye drops a tear, which them transforms into:
And this is one of my favourites; it starts off as just the title and a house, and then pulls back to have it repeated, until there are dozens in a grid. This is at about the half-way point:
Who was the unknown genius who came up with this concept? There is never a separate credit for Title Designer, so it's most likely an editor. These films don't always have the same editor, so someone must have started it. Then it became a convention that the studio felt the need to uphold; this is what people call branding, I suppose. Whoever it was, I salute thee!
UPDATE (8 July): The answer is Mat Sentul!