You can find this portal at any biome in the surface.
New Zombies Variations
The new dimension
You can find this biome close to the pocotroa biome
You can find this biome close to the desert or close to the Strange Forest
Blocks and plants of the mod
You can get this items by killing all the 3 bosses and trading the items with the mysterious villager.
You can find this biome close to the plains
One of the three bosses
All Armors.