From what I've read, it's pretty much a safe assumption that anything in the water has some level of toxicity. The only ones that I've heard of being particularly dangerous to humans without allergies, however, are Palythoas (palys), Zoanthids (zoas), and Gonioporas (gonis) - and to my knowledge, nobody in the hobby has ever actually died from these corals (though there have been a number of hospital visits related to the palytoxins in palys and zoas, typically either from aerosolizing the toxins somehow [usually through incredibly unwise and unsafe decisions] or from people getting the toxins in their eyes). A general rule of thumb, if you treat the corals with proper respect and practice good safety rules (including wearing PPE when handling and fragging the corals), you'll be fine.I was reading about palytoxins a week or 2 ago actually and would want to stay far away from those kinds of coral if I do end up having coral at some point! Are there corals that are generally safe and don't have toxins?
As for the fish, I haven't fully learnt about which ones have poison and are a bad idea for me. Clownfish are safe though, right!? (I hope haha)
In other words, most corals are completely safe to handle and have in your tank (including - for most people - the highly toxic ones), but you should always practice good safety rules regardless.