Hey. The only implemented target transforms are the differences and the local standard scaler and they're not documented. You can also define your own, you can find an example on how to do it on the end to end tutorial. I'll also add a guide soon with a class that will take an sklearn transformer to easily apply global transformations like log, boxcox, etc.
For lag transforms all the functions in the window ops library work and you can also define your own, they can be any function that takes an array and returns an array of the same length which can be jit compiled with numba. I'll also add a guide with some examples soon.
Sorry for the lack of documentation, we'll work on addressing this this month