Heo, those sockets with the U-joint built in are pretty common. I have a set by Snap-On that dates from the 70s. I'm sure you could buy them locally.
I have several sets, 1/4, 3/8 and 1/2". The 1/2" are nice for tight bellhousing bolts. Pretty handy for taking off valve covers on shock tower cars also. I use the 1/4" versions for that. With a long "locking" extension, so you don't do the inevitable drop into the Twilight Zone, it gets you outside the engine bay and away from all the heat.
Some of my best and favorite tools are from my Grandpa and Dads tool collection. If the swivel is worn, which those look to still have some resistance to the swivel (a good thing), a little electrical tape around the swivel helps them keep an angle, which makes it MUCH easier to get on hard to reach bolts.