There are a fair amount of posts about adding/altering iNat’s iconic taxa, including at least two feature requests that are open:
https://forum.inaturalist.org/t/make-crustaceans-and-myriapods-iconic-taxa/996
https://forum.inaturalist.org/t/need-for-more-filter-categories/74484
https://forum.inaturalist.org/t/question-about-categories/65024