The 1st two look like umbilical hernias.
They are caused by a defect in the rectus abdominus (usually the anterior abdominal wall closes completely when your umbilical cord is gone). These are way more common in newborns, and they are usually repaired then. Things that increase abdominal pressure (e.g. straining to take a shit, doing heavy squats) can make the protrusion worse. Worse case scenario is a strangulated hernia, where part of you bowels get trapped in the "hole." The good news is they are easily repaired.
