Plantera

This will come naturally as you progress and will be one of the last trophies you earn. Things can get a bit hectic when you have all your expansions, but remember that your workers will continue to do some of the work for you and you cannot "die" as such. Keep playing and plugging away and you will get there eventually. You are free to use the Date/Time Exploit to obtain this trophy, as it speeds this up massively. See Worth A Million, for an exploit you can use to speed this up.