I'd have to ask the friend who's hosting our server for the exact seed, but the one we're on is pretty nice. The starting island is ridiculously massive, we've still not fully explored it and we're readying ourselves to fight the 4th boss now. You have access to plenty of the first two tier biomes, a usable amount of the 3rd tier, 4 4th tier biome areas to explore and there's even the 5th tier one way up north. There's a second continent you can access through a shallow connection point that allows you to swim, possibly with a small bridge to cross. The boss location for the first three are all on your starting island and the merchant is very close on a different island. Easily the largest spawn island I've ever seen the game spawn.

There's even mini-biomes of some of the higher tier ones that make venturing into places you might not want to be relatively safe since their size keeps the mob spawns incredibly limited.