To put in these scripts as hotkeys, you need to go to the hotkey editor and put them under the USER Category.
So go to Window>Settings/Preferences>Hotkey Editor…
On the Column on the left, add the commands under the User Category, you can assign a hotkey on the right.

Hide/Unhide Nurbs Curves from Viewport

string $myPanel = `getPanel -wf`;

if(`getPanel -to $myPanel` == “modelPanel”) {

if(`modelEditor -q -nurbsCurves $myPanel` == 0) {

modelEditor -e -nurbsCurves 1 $myPanel;
}
else {modelEditor -e -nurbsCurves 0 $myPanel;
}
}

Add InBetween to Keyframes

timeSliderEditKeys addInbetween;

Remove InBetween on Keyframes

timeSliderEditKeys removeInbetween;

Hotkey to Delete Keyframes

timeSliderClearKey;

Hide motion path Marker Display

import pymel.core as pm
for m in pm.ls(type=’positionMarker’): m.v.set(0)

Auto Tangent Curves

keyTangent -itt auto -ott auto;

Smooth all Curves

aTan_smoothKeys();

Spline Tangents

keyTangent -itt spline -ott spline;

Cut, Copy and Paste Keyframes

ctrl + shift + x = timeSliderCutKey;

ctrl + shift + c = timeSliderCopyKey;

ctrl + shift + v = timeSliderPasteKey false;

Smooth all Curves

aTan_smoothKeys();