1) Credit goes to Cat for compiling the original list. Granted I couldn't quote the list directly from the post as it's been locked, but it did lay the ground work.
2) Unlike Cat's list, I have removed certain mobs that are present on the Banned spawn list (think Turkey/Chicken Oryx/and a certain gnomish fellow)
3)Note that a mobs spawn command and how their names appear in-game may differ. This is fairly common. Don't think twice just go with it.
4) Any mob I cannot find a working command for will be noted with the -Not Working tag. This tag is to ensure that you don't waste your time trying and to let the staff of the game know what's up. Please remember that if you see this tag I have tried every conceivable variation of the command to try and get it to spawn.
So either it isn't implemented or doesn't spawn under it's name or the name from the original list. This may be intentionally done by staff for whatever reason, as is their right.
Okay on with the show!
Shoreline
Lowlands
Midlands
Highlands
Mountains/Godlands
Bosses
Extra Bosses (added for fun and flavor)