Toddler Raphael. At the time Raph was the only surviving member of my original Toddler Turtles set which I had purchased at retail back in 2004. My kids at the time played with all of them and all turtles and weapons were lost in a move or elsewhere; all except Toddler Raph, whom I rescued before he too was lost forever.
Over the last four years, as my TMNT fandom has grown ever greater, I have slowly (and inexpensively) been 'getting the band back together.' Basically, if I saw them at the flea market in good condition and cheap, I bought them!
I've seen all the Toddlers turn up at the flea market at least once each. I even had two Raphs for a while (but just mailed the extra off to another huge Raph fan!) Sadly, more often than I'd prefer, they are pretty roughed up and not worth owning, even for cheap. Usually the paint on their heads is super roughed up, or their shells look like they were dragged behind the van for a few miles. They also never have their weapons.
But patience and perseverance have (almost) paid off. In addition to my original Toddler Raphael, I currently have Toddler Leonardo and Toddler Donatello - as well as Donatello's training Bo Staff and (ironically) Michaelangelo's training Nunchuku which I got from Cool and Collected in a trade.
The weapons aren't as big a deal as the turtles of course - having any of them is nice for sure - but most importantly I need a Toddler Michaelangelo to complete the team and will feel fully accomplished when I find him.
Having all turtles and weapons (without resorting to eBay prices!) would be quite the feat though!
You never know, it just might happen!