best things are the "old"manual lenses where you have aperture control on the lens it self , search for rokkor 28mm or rokkor 35mm on ebay i use the 28mm my self but i still want to try the 35mm one day :) the28mm will have a better magnification . see also https://petapixel.com/2015/05/01/shooting-insect-macros-on-the-cheap-with-a-reversed-lens/
and this also gives some nice info https://photographylife.com/focal-length-in-reverse-lens-macro-technique