Allen wrenches [hex keys] are stull commonly used. The smaller sizes are often encountered in various pieces of equipment. For instance, I had to buy a very small one for 99¢ in order to install nuclear powered, radioactive EXIT signs in a Home Depot.
For the torquing applications, I use a Sears Craftsman 3/8" drive beam type torque wrench. It is not too hard to find the smaller size of Allen sockets. But you want long sockets for instance in transformer installations. What I did is get the cheap, long L wrenches and a six point, el cheapo, 3/8" drive socket, cut off the long arm and epoxy it into the socket. It is surprising how much the extra handle length of the torque wrench helps.
What are the recommended torque vales of bolts?