There seems to be a speedrun community, some people on Twitch run all pre-hardmode bosses.
There are at least 2 different duping glitches you can do on the latest patch, one involving an item frame (must play as a server for it to work) and the other involves some shenanigans of dying, leaving & rejoining and interacting with a chest, although I don't remember which order you must do these things in... The gist is you can take contents from a chest without emptying the chest (as far as I remember).
There are also some other bugs, but the only ones I encountered are some small clipping bugs.
On the left side of the image, when jumping on the platform with the candle, it zips me to the platform with the books (below) immediately. But when you change the pattern of the candle platform via hammer and then change it back, or remove and place it again, it will no longer work. I also tried to rebuild this terrain (right side of the image) but it didn't zip.
2)
When you are underwater and you walk across this terrain, you will zip downwards:
you - - - ->
_______
/
/
/
There are also some other bugs, but the only ones I encountered are some small clipping bugs.
some small clipping bugs
When you are underwater and you walk across this terrain, you will zip downwards
Seed: 437042179
X: ? Somewhere on the left side of the map
Y: 1004 caverns
On the right in the image is my underwater hoik hellevator btw which travels me downwards. I didn't make it so I can travel upwards and instead built a house with bed (spawn point) so I can mirror there. This setup helped me quickly gather Obsidian by bringing buckets of water to the hell, or lava to the surface.
I have like 100 gold in my safe and none on my hand.
I picked the Extendo Grip that I had equipped, which had a melee speed buff, and reforged it at the tinkerer guy.
Then I placed it back in my accessory slot.
After doing so, I suddenly had a little less than 100 gold on my hand and the gold in my safe was still there.
So basicly I have 100 gold more now.