I am attempting to make a code key practice unit. I cannot find
anything out there! I am going to make a simple tone generator so I
can practice. Is this feasible? Are there any other designs out
there besides making a full oscillator?


I'm not sure what you mean by "a full oscillator." You could use a simple
buzzer or a Mallory Sonalert. The latter has a pleasant tone. I made a
mechanical oscillator out of a small speaker once by substituting a couple of
silver plated wires cut from old diodes for one of the flexible wires
connecting to the voice coil. You adjust the wires so they just make contact
normally, then wire the thing to a flashlight cell and a key, setting the
polarity so that the cone moves to open the contact. Kinda raucus(sp) but it
worked.

Doug Moore KB9TMY