These make for great NPC's, even if you don't have a need or opportunity to play one as a PC.
Up first is a real monster depending on you want to use her, we have here a Divine Paragon Cleric of Urgathoa/Evangelist PrC VMC Witch... you don't HAVE to go into Agent of the Grave for level 16-20, but there's literally no good reason not to. Anyways, this is all actually just a gimmick to get the Divine Paragon of Urgathoa access to the Blight Hex. This isn't overly powerful by any means, just fun:
Blight of Ruin (Su) Your blight hex gains power from Urgathoa’s favor. If you use your blight hex on a plot of land, you can affect an area whose radius is equal to 20 × your combined witch and evangelist levels. If you blight a creature of the animal or plant type, increase the saving throw DC by 4 and the curse’s effect to 2 points of Constitution damage per day. If the target successfully saves against your blight hex, it instead takes 3d6 points of negative energy damage. If you don’t have access to the blight hex, you instead gain the ability to use mass festerAPG once per day as a spell-like ability.
Next up, we have a Witchguard Ranger VMC Witch. Access to Patron Spells for a Ranger? Yes please. Might as well stack on a Familiar and some Hexes, too. If you choose the Plague Patron, you can get Animate Dead and go into Agent of the Grave... sorry. Do whatever you want, lots of options with this one.
Last but not least (for now, I have more), is the Eldritch Archer-Hexcrafter Magus VMC Witch. This one is thematic as it is fun. Bonus feats ease the pain of VMC, and you get access to Hexes without wasting Arcana. Free Familiar, too. Best part, is you can still get into Agent of the Grave... if you want.