They don't exist. The pills that *actually* do anything are going to come with some pretty hefty side effects up to and including death.
ephedrine - when combined with caffeine doubles as an appetite suppressant and stimulant, but the net effect on TDEE is going to be 1%. Maybe 2 if you're lucky. Side effects: increased anxiety, nausea, cramping, and potential for heart issues.
clenbuterol - you should not use this, but it is ephedrine's big brother with big brother like side effects. In addition to the ephedrine sides, you can also expect excessive muscle cramping, fatigue, night sweats, hyperthyroidism if abused, increased blood pressure and some other ones. Your cardio activity on this guy should be kept to a minimum, and you're going to want to supplement big time with additional tuarine and potassium. The world anti-doping association recognizes this as an anabolic steroid (which is stupid, it's nothing of the sort) but I do think it's equally potent/dangerous in the wrong hands. The up side is that you can get 5-10% additional TDEE in.
dnp - the most dangerous of all of them, and the most effective. You will shed weight fast, but you will also overheat. Any exercise on this guy can be *really* dangerous, and the wrong dose (which can be easy to take) will absolutely kill you. Other wrong usage sides: cataracts, lesions, bone marrow, cardiovascular and nervous system damage. It's a very strictly controlled substance in most places. TDEE increase depends on dosage, but will quickly hit zero when you fucking die from taking it.
All of these are things that I would expect serious athletes and bodybuilders to probably be familiar with, and none of them are things that a total amateur should ever consider. The only reason I'm even sharing this info is to provide info on how dangerous they are. If you don't have the discipline for caloric restriction, how can you have the discipline for something far more egregious when done wrong?
All other legal 'diet' pills will either be heavily caffeine based or just have a bunch of crap that is statistically not significant to body composition. L-carnitine, yohimbe, etc, etc, won't do what you think they'll do. The effect will be almost non-existent, and you'll have just wasted your money.
Caloric restriction is the greatest and most effective tool you have for weight loss. Stick to it.
Edit:
Here's a vice article on DNP.