You looking for a toggle style dimmer. Where the toggle lever is off all the way down and starts ramping as the lever is moved up, to full on.
Do a search with your favorite search engine.
I found many listed with a search on "toggle style dimmer". Amazon, Home depot and Walmart are a few vendors I saw.
I would check the ratings of them to make sure your load is not too much for the type bulbs you are using. Or needed a neutral power connection. Over what many switches are two wire use. Line and Load.
Ok maybe I was not clear on description :) The switch I have most in my house has this type. The kitchen one just broke and it is the regular toggle switch that has the dimmer incorporated. So if I turn it down it is off, if I move it up it is dimming the light without any second slide operation. The stores have the toggle with slide or a wider dimmer(cannot use it due to the mirror cover cut to the thin switch I have today. I think it is hard to find...