Based on Doug Smith’s research for observation 12527:
1829 – pub. Agaricus cinnabarinus (which was promoted to species from previous Agaricus granulosus var. cinnabarinus).
1870 – pub. Agaricus terreii
1889 – pub. Cystoderma cinnabarinum, new genus so species moved from Agaricus.
1978 – pub. Cystoderma terreyi, moving Agaricus terreii to new genus.
Somewhere since then, these are called equiv., And along the way a number of other pub. genera (Lepiota, Armillaria) for this species also called equiv., so the oldest name Agaricus cinnabarinus takes precedence, which was moved to Cystoderma cinnabarinum. So that is the prefered name, until…
2002 – Cystodermella cinnabarina, moved to a new genus because of inamyloid spores, and molecular work suggesting a separation from genus Cystoderma.
Since then there seems to be pub. of Cystoderma cinnabarinum, so perhaps that one is not deprecated, but just an equivalent, and all others are deprecated. It depends if you want to recognize if presence of pileocystidia promotes this to a new genus, or just a section of Cystoderma.
So, this is my understanding after 15 mins of research on this one species:
Equiv. names = Cystoderma cinnabarinum, Cystodermella cinnabarina
Deprecated names = Agaricus cinnabarinus, Agaricus granulosus var. cinnabarinus, Agaricus terreyi, Agaricus terrei, Agaricus terreii, Armillaria cinnabarina, Cystoderma terreyi, Cystoderma terrei, Cystoderma terreii, Lepiota cinnabarina, Lepiota terreyi.