Duplicates here too. Although DCs have a proper old stocking and one of DH's old football socks, so they naturally came in pairs 
Shame on all these Grandmas who made them for their GCs but didn't bother to make a spare! My DM used the same trick on me and let me in on the secret when DD1 was born. DD1's 'proper stocking' originally belonged to my Grandfather and were used as DM's stocking, then mine, before working its way along to DD1. Poor second child has to make do with the football socks, but it is the closest thing in size I could think of.
We do a switch-a-roo as we wobble to bed around midnight.