⭐ Merited by ABCbits (3)
Is this 0.0001 dust accumulation primarily due to negligence? Or is some other mechanism leading to so much of it?
Apart from the recent Ordinals Attack that contributed to a large number of small UTXOs, the old ones are mainly because of Dusting Attack. This attack is performed as an attempt to deanonymize the addresses that are sent these dust amounts. The "hope" is that the receiver would use other UTXOs from other addresses previously not-linked to the dusted address when consolidating the coins, therefore linking them all together.Quote
If anyone has ideas of other things to look into I'd love some suggestions 
Try analyzing scripts looking for non-standard/unusual output scripts, unusual signatures, and stuff like that. It could be interesting.I discovered that about 140m of my utxos seem to be OP_RETURN and have an amount of 0.00000000 but are marked as unspent (or rather, were never spent after being created). I'm guessing these were just place markers for people to add comments to the chain? I ordered these by script type and 99.9% of them are of type nulldata.
Technically OP_RETURN outputs are never included in the UTXO set because they are not unspent (ie. not yet spent, may be spent in the future) transaction outputs. They are unspendable as in they cannot be spent ever or they are provably unspendable.OP_RETURN is just the standard way of adding a small arbitrary data to the bitcoin blockchain, which is why they call it "nulldata".