This is a useful list of design myths. Here are a few relevant for presentation design (I adjusted the wording a bit here and there):
Myth #34: Simple = minimal
Myth #28: White space is wasted space
Myth #19: You don't need the presentation content to design a presentation template
Myth #14: You are like your audience
Myth #13: Icons enhance slide clarity
Myth #10: If your design is good, small details don't matter
Myth #8: Stock photos improve the audience's understanding
Myth #7: Graphics will make a slide element more visible
Photo by Alexander Schlembach on Unsplash