What is in my natal chart that shows my tendency towards hoarding, clutter, and disorganization?
Hoarding is said to be a Moon and/or Cancer 'thing'.
Organisation is attributed to Leo,
Clutter and DISorganisation would make Virgo's desire for neatness, order, and everything in its place close its eyes to it if it wasn't.
That's where I would look.
I notice that the 3 signs are heavily tenanted, yet there is a small triangle between Moon feelings (ruler Cancer), Mercury (thinking) in Cancer in 3rd house (thought processes) to Pluto (power of will) in Virgo (physical precision and detail) in 5th house (self expression).
Moon and Mercury are inclined to hold on to memories, each in their own fashion. Moon/Cancer can't throw anything away because of the sentiment or emotional security attached to the item(s). Mercury 'remembers' the events that go with the item or situation, whether it's the old bike from youth, relationships, and/or shelf full of books attained through adulthood, etc..
Others may mention how disorganised you and/or your life is. By the same token you could be exactly the opposite, providing them with alternate criticism. Yet within your own clutter and disorganisation you can probably immediately put your hand on anything you are looking for at any time, even if there isn't a square inch of space to be found. Tidy up and you can't find a thing.
There is no planet (trait) expressed through the Air element (intangible mental expression). You could put things down automatically (Moon) without thinking (Mercury) about where you have put them, through which clutter becomes an adverse aspect of character.
Mercury-Neptune in water signs may tend to mental daydreaming, escaping into a world of fantasy that takes it out of the humdrum of everyday living.
Taurus has a reputation for being slow to get moving. Sometimes it turns into plain laziness. A Moon in Taurus may not feel to have, or desire, the physical security the sign needs, so doesn't feel the mood arise to do anything to physically change a situation. With an opposition to Mars (active energy), it may just need to get its act together ...in the manner of a bulldozer ... to do something about it.
There is an aspect of character that may not (believe to) care about the physical life as a result of internal pain it produced.
There appears to be a lot of inherent anger in the chart that remained unexpressed in youth, for which other means of self-assertive energy in adulthood had to be found. Energy can be expressed and used in so many different ways ..... including discovering and directing a manner within one's self to become less cluttered and more organised ... also in feeling, mind and spirit.