Supps/vitamins etc - when on gear the body needs a much higher amount of micronutrients.
Reason:
Take peds -> system stress goes up -> receptor activity goes up.
When system stress and receptor activity increase. The body needs more vitamins and minerals to compensate and balance out the imbalances.
So on cycle. Increase your vitamin and mineral intake with diet and or supplements (most won't be getting all they need via diet on cycle).
This may include: simple multivitamin, magnesium, zinc, calcium, b vitamins, vitamin d, c, k etc
I also use fish oil for lipids and inflammation control.
Milk thistle is meh. Research on it doesn't show it being very effective.
Nac and tudca, yes, these are great. With tudca you get the added benefit of optimising protein folding which helps hypertrophy overall.
For digestion - glutamine is king. It massively improves intestinal function. Always helps me push more cals on bulk. Very very very underrated supp.
For ancillaries, nothing is more important than controlling the upregulation of the raas that peds cause. Raas upregulation is the primary cause of damage of damage to the body when using gear. Raas upregulation cause oxidative stress and inflammation levels to increase in the body which slowly damages all tissues. It also increases BP.
Control the raas via an arb or ACE inhibitor. Telmisartan is the best option for this.