True Hardcore

Features

Beds 

like in the good old days of Minecraft, where hardcore mode didn't support beds. You can still craft them and lay in them, but nothing happens

Totem of Undying 

no longer obtainable by killing Evokers

Shield 

can no longer be crafted in the crafting table. It can still be obtained by trading

Mending 

no longer obtainable by trading with villagers. It can still be obtained every other way other than trading

Phantoms 

because the player cannot sleep, phantoms will spawn only rarely, approximately once every 10 Minecraft days making them less annoying and useful for repairing Elytra before getting mending books