afni.nimh.nih.gov

An easy way to get a listing of all ROIs across all of the atlases that you have loaded is:

whereami -show_atlas_code

Hypothalamus isn't that common in the atlases that I usually look through, but you could take the TT version and transform it using either 3dWarp's -tta2mni option or by creating a transform (preferably with either auto_warp.py or 3dQwarp) and apply that tranform to move your region of interest from one space to another.