Archmage Delving into Secrets Man Was Not Meant to Know - This is the fantasy equivalent of a mad scientist, whose field of research is unwise or safe. A Lich can be a subtrope of this, or the Lich might be a subtrope of 'conquering warlord' (or both) depending on how exactly the Lich is using his magic and his ultimate goals. Xykon from 'Order of the Stick' is principally the unwise archmage delving into secrets best left buried and untouched, but he thinks he is a conquering warlord.
Created Sentience Hostile to Its Creator - One possible result of unsafe or unwise magical research. Marvel's 'Age of Ultron' is a baddy of this sort, as is Frankenstein.
The Manipulative Minister - The villain here is operating behind the scenes and manipulating 'The Powers that Be' to his own ends. In a fantasy, this can include anything up to the level of deceiving the Gods, provided the Minister in question is sufficiently epic. A suitable villain for a game that is primarily political, and also makes a good 'surprise' villain to come from behind the curtain if the PC's manage to easily kill the guy that they think is the BBEG. religon's 'A Demon in Our Midsts' is sometimes a figure of this sort, though its equally if not more frightening to make the character human (or once human). Common roles include The Prime Minister, The Arcane Advisor, The High Templar, The Consort, or the Grand Inquisitor. Hans from Disney's Frozen is an example of a villain of this sort, as is Jafar from Aladdin and Flagg from Stephen King's various fantasy stories.
The Nihilist - If whom this figure is usually someone who is the victim of some unjust cruelty who as a result believes he has lost everything he has of value and so may justly destroy everything else everyone else holds of value. This can go up to an include destroying the whole world, though sometimes the aims are more limited like - all members of a particular family, all members of a particular race, a government, everyone however minor related to the crime against him, etc. Sometimes justice is intended to be more poetic, for example rendering blind everyone since he is been rendered blind, or transforming everyone into some nonhuman form since he has been rendered nonhuman. Often played as a figure of some empathy or a tragic villain, as for example 'Mr. Freeze' from the Batman cannon. Occasionally The Nihilist leads an organization of like minded individuals, in which case he's likely to turn out to be 'A Demon in Our Midst'.
The Uncaring Universe: Something has gone wrong with the universe or nature and its set to annihilate life not out of malice, but simply because. This can be literally anything, but in a fantasy story usually has to do with the laws of the universe being fundamentally altered in some fashion. Since the average fantasy universe is animistic its difficult to depersonify catastrophes but with a bit of work, you can have even the gods helpless - indeed, 'all the gods have gone missing' would be one example of such a plot. 'The Nothing' from The Neverending Story is one example of such a villain.
