Here is the idea for Quark:
Remove the RunicEtching duplication craft and so that they can be obtained in more places such as ship chests, fishing and via a cleric for 15 emeralds.
Add a new trumpet tree with white leaves in the mountains.
No more flowers for the sniffer.
Add cracked red and blue netherbrick as well as their chiseled with a blaze head for the chiseled red netherbrick and an enderman head for the chiseled blue nether brick.
Add the natural generation of soul sandstone in the soulsand valley under the soulsand and soulsoil.
Add iron ore from the nether which will give iron nuggets found at the lava level.
That witches can spawn in the nether in all biomes with the same spawn rate as in the overworld.
That we can repair a trident with prismarine shards via an anvil.
And last idea, wool has patterned blocks of wool with patterns also existing in carpets obtainable only via trade with shepherd villagers.
Sorry I used Google translate for this post.