Shadowdragon said:
... but most of them are beyond my knowledge. Web sites with bestiaries for creatures from ancient mythology (in particular - Greek, Egyptian, Persian, Celtic, and Norse) would also be very helpful.
Encyclopedia Mythica is probably the best web based source to start with. Check out that 1001 non-RPG Sites list as well.
A number of monsters in the Monster Manual are taken from general european myths; ogres, trolls, bugbears, goblins; stuff like that. Most of course have a unique D&D spin (I've never heard of the regenerating-from-pulp troll outside of D&D).
Stirge and Erinyes are Greek in origin; one is a type of vampire, the second are another name for The Furies, the Greek spirits of retributive justice. Obviously, sometimes the MM just uses the 'cool name' and drops everything else, adding to the confusion (The name for the aquatic Ogre is a case in point; the merrow is an Irish water fairy). Gorgons, for instance, are nothing like the original Greek monsters (of which Medusa was just one of three). Lamia (which is really more like the Greater Lamia than the horse/dog thing pictured) and harpies are also Greek.
Manticores (aka Androphagus; both names mean 'man eater'), hippogriffs, chimeras; most of the 'part of this animal, part of that animal' creatures are from Greek myth, sometimes transmogrified by midieval mysticism.
The Naga and Rakshasa are Indian in origin.
The Displacer Beast, it's form at least, is identical to the Coeurl from A.E. Van Voght's short story "Black Destroyer".
Kobold is a shortened form of a German word for earth spirit.
Frost and Fire giants from Norse myth; arguably, dwarves and elves as well.
Green Hag and Annis are both welsh/irish/british like most of the fae creatures mentioned, including brownies, pixies, etc.
Golem, clay from Jewish kaballistic practice; flesh golems of course from Frankenstein.
Angels/planetars/solars/archons from Christian apocrypha and various midieval beleifs.
Salamanders were an alchemical creature, I think. So was the cockatrice. The elementals are probably from Greek myth in some form.
Efreets and Djinns are from arabic tales and the Bible/Koran (probably apocrypha crossed with some middle ages mysticism; Soloman was suppossed to have made his name by bottling up the various old spirit creatures with the famous Seal of Solomon; thus we wind up with the genni in a bottle myth).
The couatl is Aztec.
Ghoul is from the Arabic 'ghul' I think.
Check out some folklorist sites as well. Many, many times the MM (as I said above) uses the cool name but actually has a totally original or different monster behind it. And a single creature may have many, many names, depending on the person who wrote down and compiled the legend; this is from regional and language variation. Sometimes celtic faerie creatures would have almost mundane sounding names (such as Jenny Greenteeth or Jack In The Green), actually refering to another creature that dare not be actually named or it might hear and respond. And sometimes the alternate name was given to modify any perception of ill respect; most fae folk were simply called 'The Good People' or 'The Good Neighbors' lest any be hearing and bring down curses on a family who named them or accussed them of evil.
