The very first time I used parts.io, searching for MOSFETs, in that first instant after clicking the main Transistors category icon, then saw all the various transistor type sub-categories, I thought "great, they've got the electronic symbol for each type, & there's my beloved MOSFETs!". But no, after a few more seconds of confusion I realised the symbols for all types of transistors were the MOSFET symbol wtf?
Compared to the minimalist clarity of the top-level category icons, it was confusing, off-putting, and disappointing, approximately in that order
Now this morning I'm All About Switches :). Again, there's the pretty, simple, unambiguous Switches main category icon. But under that, 24 sub-categories that all have the same symbol.
I realise it probably isn't possible to create representative icons for the subcategories of ALL the main categories (like, regulators - ugh...), but for some, it is, and I would urge you to consider this. if not a symbol, then perhaps an 'impressionist' drawing of what a typical member of the sub-category should look like.