Minecraft

In order to obtain this achievement you are going to want to start off by creating a new world with the following settings:

Default Game Mode: Survival
Difficulty: Peaceful
World Type: Infinite
Seed: 1204739880 (or just click the arrow button on the right and select Savannah Village from the Seed Picker option)

This will start you off in a world with a village very close and a river running near by. Your first task will be to get a handful of raw fish by simply jumping into the river and looking for fish swimming around. You are going to want to melee each fish 3 times in order to get them to drop what you need. Once you have around 15-20 pieces of raw fish I would then suggest you travel to the village located nearby and create a save and then quit the game.

What you are going to want to do is manipulate the save by making a duplicate of it and then using that duplicate file to feed the raw fish you have obtained to the stray cats in the village. In order to do this, just select the little pencil/pen icon on the right side of the world's save file and scroll all the way to the bottom to the option that says, 'Copy World'. This will create a duplicate save.

When the above has been done, simply load up the duplicate save. When you have spawned, make sure you have the raw fish you have collected selected and try to locate a nearby cat and crouch nearby it using . Do not push up too close on the cats at they will get scared and flee. When a cat gets close enough, aim at it and press the button to feed it the raw fish (the cat will have love hearts when it has been tamed and may take multiple fish to do so). Do this for all the cats on that save within the village and then save and quit.

Rinse and repeat the above process by copying the main save and creating a duplicate file until you have fed a total of 20 stray cats. This method speeds up the process without needing to farm raw fish each time. From scratch, this should take approximately 30 mins.

PLEASE NOTE: My achievement tracker did not go up after taming each cat, but did give the achievement as soon as I had tamed 20 cats.

ACHIEVEMENT WORLD
Thanks to Shadow Kisuragi for making the first version. I've upgraded and optimized it. Download it from here (version 1.11.0) Will add a Win10 and WP version later (.mcworld)
https://www.dropbox.com/sh/yxsai6n63njgqyv/AACXlcX_oOzsZrTS7...

LOAD THE WORLD ON EASY!

I've run over once with a 2nd account, my 2nd account now always spawns nearby, not sure if it is for everyone. Upon spawning, you're at coordinates 554, 69, 381. Over here (other side of the wooden structure), feed fish to the cats in the 2 holes until you've tamed 20 of them.
PLETHORA OF CATS

Interact with one of the 2 grindstones on top of the wooden structure. Place the enchanted sword and the regular one in and extract the regular sword that comes out. DISENCHANTED


Now kill the creature (pillager captain) inside the wooden structure I'VE GOT A BAD FEELING ABOUT THIS

Now head over to the village at 560, 70, 466. Upon entering the village, the raid will start. During the first wave, you'll earn WE'RE BEING ATTACKED

Survive the 3 waves of pillagers. The iron golem kills quite a lot of them as well. Also, pay attention to what direction the pillagers spawn. Sometimes you can't find the last one, he can usually be found in the direction that the pillagers spawned in that wave. In wave 3, you have a chance to pop KILL THE BEAST Otherwise, spawn one in with the eggs in your inventory.

Everyone who killed at least 1 pillager during the raid, will get the hero of the villagers effect upon completing the raid. This is needed for the BUY LOW, SELL HIGH achievement. Find one of the two villagers to trade with. The pillagers who you killed earlier dropped emeralds, otherwise kill cows which are usually in the village or harvest carrots. Trade one of the discounted items with one of the villagers to get this achievement. You will lose the effect if you get too far away from the village!


The last achievement can be a bit buggy. SOUND THE ALARM You need to ring a bell while an enemy is in the village, thereby forcing a villager to hide inside one of the houses. What worked best for me was to dig a 1by 1 hole at around 561, 70, 471. Spawn a stray in there with the spawn eggs. Place a bell next to the hole and ring it. The villagers should enter the 2 houses nearby. A good indication of it working is green sparks coming from the bell or the villagers. If it doesn't pop, try to push the villagers out, respawn the enemy or move locations with the enemy and bell.

On to the next update

Stray Cats can be found at any village.

Take them by standing still, crouching, and holding raw fish in your hand. Wait for the stray to approach you, and press left trigger to tame it. Once it sits and hearts appear above its head, it is tamed.

Do this 20 times, and you will unlock the achievement. It will probably take more than 1 village to find enough strays, but simply run around your world, or start new ones with village at spawn seeds to farm this one.

Congratulations, you now have an extra 20G!