This past year I have been creating my own manga and I wanted to watch some great mind indulging animes. With these I hope to be able to create a unique, elaborate, and suspenseful plot.
A few strategic animes I've seen are: Death Note, Umineko no Naku no Koro Ni, Mirai Nikki, and Higurashi
Obviously violent scenes/gore is not an issue (in fact it's slightly encouraged)