Probably the oldest thing that I still use in the winter is a
KW 2029 Robe made from terry cloth in 2003. The print is of coffee beans and various coffee related words. I still have the pattern and was thinking of making one in silk for the summer but have yet to get to it.
Outside of that I have SF Giant baseball logo'd t-shirts from the 90s that I haven't worn in years but keep them for nostalgic reasons. I also have a bunch of printed 3/4 sleeve
Glima tops that I bought 10-12 years ago. At the time they were made in California but no longer are because their printer closed. I used to wear these and then quit after gaining a few pounds. This winter I brought them all out and wore them again.