One of the greatest mods for one of the greatest games of all time. Many Terraria mods necessitate QOL mods in conjunction, and calamity benefits, but it adds its own form of QOL in changed recipes and new recipes for previously uncraftable items. However, the removal of NPCs selling potions is a poor decision on the part of the dev team. This just makes Calamity less of an all-in-one experience. I am currently undergoing a Calamity playthrough with no other mods (except Calamity Music) to see how effective Calamity is now as an exclusive, one-mod experience. Nonetheless, the content is great, with improvements on vanilla bosses, new bosses, multiple new difficulties, great new weapons, armor, and accessories, and a lot of postmoonlord content. I specifically dislike the early game because of its slow pace, with the pre-boss stage easily taking longer than the stage between any two bosses. I am very impatient, but Calamity is worth going through it. All told, I'd give Calamity Mod a 92/100.
I was originally listing each boss along with a proposed set of weapons, armor, and accessories. However, many good sources already do this, so my niche doesn't exist. See here artciles and musings about Calamity, which are distinctly not boss guides.
People regard Hermes Boots as one of the best accessories in Terraria. And though this is true due to its upgrades throughout progression and every major content mod adding further upgrades to it, this is not true because of it in itself. Magiluminescence is a better alternative for the earlygame, certainly until Spectre Boots, but possibly until Terraspark Boots. I refuse to look at the stats, but psychologically Magiluminescence feels better. Try it yourself in your next playthrough! The simple crafting recipe of 12 demonite/crimtane bars and 5 topaz is very cheap and accessible preboss. The fast acceleration and stop speed is huge for bosses.