The tenth anniversary seed (celebrationmk10) is made out to be easier than a normal world when you look at the wiki with the only listed changes being that chests give you items of the best modifier and the world is painted (Also you start with different NPCS) However there are many more changes, so here are the ones I’ve experienced so far. The shimmer is much more common, you spawn on the beach rather than the middle of the world, living trees are super common and on large worlds border each biome except the beach and the forest, king slime with get smaller as you chip his health away, The Eye of Cthulhu is significantly smaller, the brain of Cthulhu is a little bigger than the player and the creepers are super tiny, and lastly pink bouncy boulders exist instead of normal ones and are pretty much insta death in early pre hardmode.

Skyblock + Dont Dig Up is the recipe of Satan

I mixed the drunk and party seeds. Pretty cool until you fall straight into the cavern layer Lol

Seed - 2.1.1.9.491748589

Edit: It's only half the world that is shimmered! Still way cool.

2.3.2.732952579

3.3.2.25.1717475132

Two Pyramids East, Sword Shrine in the West

To open the seed menu, press the seed icon in world creation

Secret seeds (available by typing the name in the seed)

To combine secret seeds, type the name, press enter, and type another.

moretrapsplease = ACTUALLY no traps

we don’t even test for that = 1/7 chance for a portal gun to be in a chest

doesthatsparkle = surface hallow

doubledaringdangers = 2 dungeons that lead to multiple biomes. it has been fixed (i recommend playing in journey mode without biome spread so that it keeps the biome tunnels)

fishmox = no world evil ❤️

abandonedmanors - bigger underground houses

negativeinfinity - negative paint on everything

hocus pocus - halloween

jingle all the way - christmas

whatahorriblenighttohaveacurse - vampire

royale with cheese - pvp map with random team starting positions

bring a towel - rain

the care bears movie - lots of floating islands

arachnophobia - no spiders, 4 or more seeds makes MORE spiders

xrayvision - light EVERYWHERE

i am error - bugs, start with old man

beam me up - teleporters???

rainbowroad - everything is iridescent rainbow

winteriscoming - permafrost

monochrome - everything is gray

toadstool - overground mushroom biome

planetoids - planetoids

nightofthelivingdead - blood moon. natural graveyard

how did i get here - random spawn

waterpark - flooding

truckstop - poo blocks

jaggedrocks - jagged worldgen

too easy - starts in hardmode

savetherainforest - giant living trees

molepeople - start underground, no surface

suchgreatheights - world generates in space layer

pumpkin season - there’s pumpkins

Notable Seeds

Life Crystals

Skyblock + Fishmox

Spawns life crystal islands

Eazenith

Zenith + Fishmox + Skyblock

Also has multiple islands that can have life crystals

Low Heights

Great heights + Vampire

World generates closer to hell instead of in space

Skybases

Royale with cheese + Skyblock

Multiple islands for different teams

Hellblock:

Skyblock + Remix

Start on an island of flesh and ash in the underworld

Beeblock:

Skyblock + Bees

Start on a mud island in the sky

Vampireblock

Vampire + Skyblock

Start on an underground island

Treeblock

Rainforest + Skyblock

Starts on an island with a living tree. Add toadstool for mushroom islands in the cavern

Flooding:

For the worthy + Constant

Rain floods the world when above 50%

Super Shimmer:

Drunk + Celebration

Water is replaced with shimmer on one side of the world. Start with the painter

Underground Islands

Mole people + Carebears

Floating islands are embedded in dirt

Evil be Gone, Halloween Edition!!!

fishmox + beammeup

Strangely, adds halloween when combined

All Combos:

Sky block + Remix = Hellblock (island in hell with ash and flesh blocks)

Bees + Drunk, For the worthy, or Traps = just both

Bees + Celebration = start with witch doctor instead of princess. other than that it seems to just merge both

Bees + Constant = seemingly just a combo. exiting this changes the screen back and gives you an achievement

Bees + Remix = seems like just don’t dig up. has crispy honey + honey pools though

Bees + Skyblock = mud and hive block skyblock

Drunk + Celebration = new music!???? heart clouds????? trippy world generation menu??? start with the painter as well. sand is rainbow, lots of shimmer!!!

Drunk + Constant = also trippy. Start with mechanic. Also has the new music

Drunk + For the worthy or Remix = just a combo

Drunk + Traps = rainbow nyan boulder

Drunk + Skyblock = start with party girl

Celebration + Constant = start in the forest. constant state of party??? Hardcore characters only lose 60 health on death

Celebration + For the worthy = BIG dungeon entrance (Nevermind, that’s just a variant). Overground pyramid

Celebration + Traps or Skyblock = just a combo

Celebration + Remix = start in hell with the tax collector instead of the guide

Constant + For the worthy = it took a really long time to grow spider caves, like a really really long time. I think it’s just a combo??? ALSO FLOODS ABOVE 50% RAIN. Adds a graveyard

Constant + Traps, Remix, or Skyblock = just a combo

For the worthy + Traps = HUGEEE dungeon entrance (nevermind, that’s just a dungeon variant)

For the Worthy + Remix or Skyblock = Just a combo, removes the solidifier and shimmer in skyblock though!!!

Traps + Remix = Just a combo

Traps + Skyblock = Lots of dart slimes

Rainforest + Skyblock = tree to hell

Some secret seeds were found in this comment:

https://www.reddit.com/r/Terraria/s/klMoxp0oOf

Been looking for a while and still cannot find it.