Their web site has got to have the worlds worst search function!
I can never get it to work right with a key word, but will most of the time if you know the item #.
I will watch the sets much closer now that I know.
Appears to be back up now.
http://www.harborfreight.com/10-piece-12-in-drive-metric-deep-wall-impact-socket-set-67915.html
this is the set that I was referring to. Gets a lot of love on here because it's cheap, Cr-Mo, and apparently the sockets are actually good.
But sizes are 11mm, 12mm, 13mm, 14mm, 15mm, 17mm, 19mm, 21mm, 22mm, 24mm
OK, so I *almost* never use the 16... but the 18 is crucial. Not only are some fasteners that size, but it's the one you need when you need to remove one of those stainless-capped lug nuts with a 19mm nominal size, and you have to peel the cap off because it's stripping/spinning. I have done this so many times I can get that damn cap off in about 30 seconds now. Who invented those damn things anyway? Same with 20/21. Don't know that I really need the 23, but still. I want ALL the sizes. (and I have them, at least 10-25mm. Then I think it skips to 27, then I have a mishmash of random branded axle sockets above that.)
16mm still is a legit size... ANSI/ISO for M10. 18 is ANSI/ISO for M12. 20 isn't standard for anything, so I'll let that one pass, but sometimes you need it anyway, likewise for 23.
Pretty much have to have all the standard sizes for ANSI/ISO, DIN, and JIS if you don't know exactly what you need a set for, and rather than try to keep all that in my head, I just prefer to buy wrenches/sockets that come in sets that don't skip sizes (or, in one case recently where I bought the Craftsman stubbies, I bought a S-K stubby to fill in the missing 11mm. My OCD side really was pissed that Craftsman didn't make one.)
To the OP: really the only solution is to go to Sears or Lowe's - and the latter is really more appealing lately, only reason I still go to Sears is to warranty stuff or to pick up one of those screamin' deal online orders - and buy some singles to fill out your set. Unless you want to order online. Even Sears doesn't sell all sizes though... I think it's the 20mm chrome socket that I had to get Snap-On, one of the few Snappy tools I've bought brand new. Just knew that if there was an empty space on the rail I'd end up needing it someday.