Pack-rat

[pak-rat] /ˈpækˌræt/

verb (used with object), pack-ratted, pack-ratting. Informal.
1.
to save in the manner of a pack rat:
I’m looking through the stuff my grandpa pack-ratted away in the attic.
noun
1.
Also called trade rat, wood rat. a large, bushy-tailed rodent, Neotoma cinerea, of North America, noted for carrying off small articles to store in its nest.
2.
Informal. a person who saves things that are not needed or used but that may have personal or other value.
3.
Informal. an old prospector or guide.
noun
1.
any rat of the genus Neotoma, of W North America, having a long tail that is furry in some species: family Cricetidae Also called wood rat
n.

common name for the North American bushytailed woodrat (Neotoma cinerea) 1885, from pack (v.); so called from the rodents’ habit of dragging objects off to their holes. Used figuratively or allusively from c.1850 of persons who won’t discard anything, which means either the rat’s name is older than the record or the human sense is the original one.

noun phrase

A person who cannot discard anything acquired; a compulsive keeper and storer (1850+)