Sometimes people create them as proxies for rare cards they cant afford, though that might raise a few eyebrows at official tournaments
Jaya, Fiery Negotiator Our highest- scoring planeswalker is this fun walker with FOUR abilities, which is usually a recipe for success at the kitchen table (Chandra, Torch of Defiance also a four-drop)
Lolth, Spider Queen There is a lot of Dungeons & Dragons lore about Lolth, and part of that is that she's mother to some drow goddesses
A fine role-player, Avacyns Judgment is no Bonfire of the Damned
This one ran across a cycle of gotcha cards that each had two words in their names that you got gotcha'ed if you said either of them (gotcha was a mechanic that allowed you to get cards back from the graveyard if you caught the opponent doing a prescribed thing and yelled out "Gotcha!")
At the beginning of the next end step, if any of those cards remain exiled, put them on the bottom of your library in any order