Selection tool proposal => Select Half

Often you may want to select half a mesh by whatever axis is relevant. This may be so you can delete it to use a mirror, and perhaps perform some cleanup on that half before mirroring. Yes, you can symmetrize, but not always. Sometimes you need to cleanup middle verts or other, then mirror.

Anyways, I've found myself searching for 'Select Half' functionality - via any relevant implementation such as 'select by Axis' would be very nice where you can choose an axis and set a value and comparison type