Don't bother with the other T numbers. For example T4 is for long term use of an inactive thyroid treatment. 100mcg T4 is like 25mcg T3 and in the real world you don't even get the same results. So just stick to T3.
For "fat burners":
Clenbuterol and T3 are relatively safe to take presuming you keep within moderate dosages I.E. under 100mcg on both. Do some more research into these so you can assess tolerance and taper them up safely to higher dosages. I would recommend only these two.
The last of the "fat burners" is DNP. History behind it was to keep the soldiers warm during times of WW2. That being said... It can cook you alive. So either do your research PROPERLY on it or avoid DNP.
Injectable steroids which help regarding fat loss is just a moderate dosage of Test to have the body favour muscle over fat and of course; Tren, Anavar & Stanozolol but these are more diet dependant.