Anything and everything Washington Senators. I have a large collection from when I was a kid that's mostly junk wax, but thankfully was really into vintage (pre-1971) as well, so I've got a few full Topps sets from 1954 to 1968, along with way too many other vintage items.
Always interesting in Senators cards / other items that can continue to round out my collection, especially a lot of the newer signature cards that seem to be released every year.