Flat Craft

This mod makes you able to beat minecraft in a super flat world by adding a new villager profession, that can trade obsidian for a nether portal and end portal frames for an end portal. But it also adds a new block, called the stone compressor, which is used as the working station of the new villager profession and crafted using three gold blocks at the top, one oak wood in the middle, one iron ingot left and right and three pieces of mud at the bottom.

Apart from that because of you needing ender eyes to beat minecraft the mod makes blazes spawn natural in nether wastes on top of magma cubes, which can be turned of using one of five new gamerules of the mod.

Another feature is, that the nether is entirely flat with this mod, highly increasing the mob spawning there, making it even more difficult.

The mod also makes lava convert into blackstone, when placed in the end or the overworld, which can also be turned off using the extinguishLavaInOverworld gamerule.

Two other features are, firstly that pillagers have a random chance to spawn with, more or less powerful firework rockets depending on the difficulty, during a raid, which can be turned off using the enablePillagerFireworkRockets gamerule and secondly that witches can drink four new potions, being the slow falling potion when she is falling, the turtle master potion when she has only half of her health, the regeneration potion when she has the poison or wither effect and the luck potion when she is traped in a cobweb, which can also be turned off using the enableCustomWitchPotions gamerule.

And last but not least you can throw different materials like blackstone, mud bricks, quartz, sandstone and red sandstone on top of the stone compressor, that is turned on using right click, converting them into their stair variant with 4/3 times the original item count if it is divideable by 3 or else converting them into their slab variant with double the original item count. But of course this can also be turned off using the enableStoneCompressorRecipes gamerule.