In my comp days , I loved clenbuterol. Good ol spiropent tabs were my go to fat burner. I went on vacation once in cancun and bought loads of it and brought it home in my suitcase. I took all the tabs and put them in a vitamin c bottle LOL. That was 20 years ago. Now days its easy to find, I think.
Anymore all I take is caffeine. Best fat burner is still physical work.