Liches are fun, but there's always pesky adventurers trying to steal/destroy the source of their undeath.
I have a lich, squirrelled away in my big pile of villains, who takes a rather unique approach to keeping his phylactary safe. Instead of securing it in a well-protected part of his lair, he disguises it as a silver piece and places it into circulation. Accompanying his character sheet is a great big table of possible locations for that silver piece to be. My particular conception of this lich is as being a caster with a firm grasp of how to manipulate luck, often having several spells in reserve that allow him to improve or reroll the results of any die roll (including those made to determine where his phylactary may be at any given time). This often results in his phylactary being safely tucked away in the vault of a wealthy someone, who will ignorantly use his resources to defend the lich's most prized possession or in the hands of some random commoner among thousands in a city or millions on a plane, potentially half a world away from the lich.
Occasionally, I'll make the coin fit the luck-manipulation theme of this lich, describing it as a double-headed silver piece.