If in those PED's you wanna include more than AAS, then, without a doubt, DNP is by far the worst... instant damages if abused.
Same with strong diuretics such as furosemide (LASIX) or too high doses of potassium sparing ones... that could kill you, literally.
To a lesser extent slin, though it's much easier to play it safe just by keeping carbs on hand... with diuretics, it takes a bit more than just water and salt to get you back to life when shit happens...
As for AAS, I'm with AshopRep, hard to tell which ones are really the harshest mg for mg.
But you can certainly say that at high doses, SHORT TERM sides will be more obvious with certain compounds, including TEST... massive water retention (even on strict diet) causing high blood pressure and all that goes with it (mainly renal and cardiac issues). AI's and ACE's will definitely help but to some extent only (not to forget too much AI's ain't good either).
Liver health is quite hard to assess without blood test/scan.