Those in #! and #4 are called "tiebars". Many types of pins or stuff like the metal leads inside of plastic flatpacks are partially constructed, plated, and assembled while on reels. These pins or leads are attached to these tiebars. The holes, I believe, are sprocket holes. After plating, the pins are trimmed or removed from the tiebars, leaving the tiebars as manufacturing scrap. Some tiebars have gold or silver on them and some don't. Usually, the base metals are copper alloy or Kovar (magnetic). With the reels, the pins can be plated only half way or the leads can be plated only in the center, to coat, in a circle shape, only the areas that the silicon chip or the wire bonds are attached to.