I keep dossiers of information on entities that I communicate with, and those that are notable or important in some way. This is by no means an exhaustive list of all the entities out there. Among them, some dangerous entities are listed, however ample warning is provided on their pages; it pays to be aware of negative entities, but I do not recommend you communicate with them.
Disclaimer: Astral Entities, like humans, have personalities, moods, and tendencies that must be navigated. They cannot be expected to like or be welcoming to everyone, although etiquette goes a long way. Should you choose to summon, invoke or evoke an entity, you do so entirely at your own risk.