Pudding Control Sample measurements
The ratio of egg/cornstarch to milk essentially controls the thickness of your end product more egg and it ends up like a custard, more cornstarch and you end up with a pastry cream.

You could swap out egg/cornstarch for gelatin?

With just yolk you add a richness to the pudding same with the butter.

With the milk you could swap it out for almond milk, coconut milk, kahlua ...

I'd also suggest a little salt to enhance flavor and maybe a splash of vanilla...

I'd also look into mousse, custard, Bavarian Cream all essentially have the same ingredients but with slightly different outcome.

That should keep yeh busy for awhile :P