Common names on this list are brodifacoum, bromadiolone, difenacoum, and difethialone.
A similar but safer first generation coagulant is Warfarin, sometimes used as a medication to treat venous thrombosis.
It all boils down to an industry measurement called LD50 which stands for “Lethal Dose 50%” which is a data based measure of the amount of grams of poison per kilogram of animal bodyweight in which 50% of cases die (illustrated as g/kg or mg/kg in charts). Ideally, the LD50 is very low but also still effective in killing mice and rats. For example, LD50 for dicofol, Kelthane, Kelthane MF oral intake is 570-595 mg/kg, so a rat which weighs up to 800g will likely die if it orally consumes more than 476 mg. At the same time, a Black-shouldered Kite bird of prey could potentially die from merely eating intestines of the rat.
There are other measures which make some poisons better than others such as discrimination: being more effective on the target than other types or animals, low resistance: some animals will adapt to poison if they eat a low dose and survive, and degradability: if the poison can break down easily then it’s less likely to have secondary victims but it also loses effectiveness faster.
The perfect poison does not exist, but some should be banned due to their harmful consequences. The ideal poison would discriminately kill rats, be stable when dry but break down quickly after being ingested, and have a low chance of resistance forming.
Yeah, it was very clearly a critique of capitalism.