BDSM is 99 44/100ths in the mind of the participants
Over several years in the lifestyle (and having had the good fortune of being the roomate of a pro toymaker at one point) I've accquired quite a sizeable toy collection
My usual comment when someone either effusively praises said collection, or when I show up without it & someone bemoans its abscence, is that, while the toys are FUN, they are superfluous
A good Top should need nothing but his/her hands and voice with a suitably evil mind to guide them
And frankly, those are all I have ever used for the most intense scenes I have ever had
The biggest turn-on for me has got to be seeing the dread/fear/anticipation in their eyes.
I might attach a pair of clover clamps to a subs nipples and then set up a drip tube to slowly fill a container attached to them. They can see that the weight is going to increase and the pain become more intense but don't know how much. For this to work, you can't repeat the same thing on the same sub or they will know what to expect. Be creative!
I also like to set up situations where a sub can avoid pain for a while or they can trade it for a different kind. Example: putting them in the 'roman chair position' with a large dildo poised to penetrate. The longer they can maintain the postion, the longer they can avoid being penetrated. Eventually though, they will have no choice as their legs fatigue. You might want to offer additional incentive like subtracting whip strokes (start with 50) for each minute they can last.
One of my biggest turn-ons is putting a sub in a position where they have to choose one of two unknown evils. (I'm kind of like a sadistic Monty Hall!) Behind door number one is...(drum roll)... Nipple Clamps! and behind door number two is ...
I also like to use My voice as a tool.
Soft and gentle or sexy and demanding.
Telling him to remind me to spank him later also works nicely.
As does telling him of a scene that I am planning and waiting to see how long he can go before asking about it.
A look, a tone of voice, the anticipation of what may or may not come all add spice to the scene. The toys are icing, but it is what is happening in our minds that is the key to the eventual outcome.
Trusting someone to the degree that I have given complete control over to him is a turn on as well as a means by which to find serenity.