Here's everything you might ever need to know, (you probably know most of it though)
You used to be able to crash the game by hitting a fishing pole on a nether portal
You used to be able to duplicate things by taking them out of a minecart chest as soon as is goes in a nether portal
Shulker boxes duplicate if they go through a portal
Minecraft used to have a pyramid that was the only structure
There was a bug that was patched up that made sinkholes in lakes or mountains
There was a bug that sometimes made half of a shipwreck on the ground and half in the air
Strongholds are generated in a ring pattern on Java, but on bedrock the generation is completely random
End cities are generated in a hashtag pattern accross the end
Mobs like zombies and skeletons used to run away if a creeper was going to explode, but it made the game laggy so it was removed
In one of the first versions, skeletons didn't have bows but still shot arrows
In one of the first versions, zombies could sprint but players could not, spiders were slower, but could jump far
There was a bug that allowed players to look like they died in creative mode if they swam in lava
The better lighting mod got mojang's attention and they added it to vanilla
Sometimes lanterns would go dark in caves for some reason
In LAN worlds, there was a bug that made it rain for one player but not the other
Tnt, carpets, string, tripwire hooks, and shulker boxes can be duplicated using glitches
. . .
I'll let you know when I have more facts about glitches and bugs and stuff
