Pretty much anything that passes through my door. I'm a HUGE packrat. I still have a huge box of my son's baseball cards, I have everything that has meant anything to me since I was a kid (things like my first piggy bank, a watch my first "real" boyfriend gave me, sharks teeth found over the years, etc.), I have all Christmas and birthday cards I think I've ever been given, drawings and report cards of my son's going back to preschool....I told my family I should probably start tagging stuff so they know what it is when I go ;)
I also collected antique quilts until they started overflowing boxes, I like Howard Finster originals and other folk art, and all kinds of travel trivia souvenirs of my trips and trips of others. I have a great nesting doll from when my brother went to Russia that has 16 dolls with the smallest smaller than my pinkie nail
And pictures - have tens of thousands of those.
Yes, I have a storage room down the road I pay $35 a month for after I moved into this little house.