Xanthan is the best if you need non-toxic slime for artistic purposes (e.g. Halloween decorations).

Just make a stiff gel and hit it with a stick blender for desired consistency and lumpiness. This does introduce a lot of small air bubbles in it, so if you need clear slime let it stand for a few hours.

In premium ice cream you'll get 18-20% dairy fat content and no gums. In ones with gums, it's typically much much lower - 5% is the minimum in the UK for "dairy ice cream" where 100% of the fat must come from dairy but notably many things are just "ice cream" which allows substitution oft the dairy fat entirely for coconut or palm oils. Adding the gums allows them to do this because it gives the mouthfeel of creaminess.