I like names that roll off the tongue with a certain weight or solidity–for instance, at the start of the campaign I’m currently running, there was a pro-nonhuman Robin Hood avian named Iiriak (EE-ri-ack), who squared off alongside the party in the second session against a crime boss named Berlenger. Also in that arc was Executor Aia Marsh, an intimidatingly competent spymaster of the empire with whom the party had an uneasy relationship–they collaborated with her a few times, but in the end she tried to arrest them for various crimes and they fled the city as fugitives.
A couple of plot arcs later, with a different party (we’re doing something ambitious with this campaign where the players rotate between several parties of characters that I’m trying to lead together into one location to see how they bounce off each other for the campaign’s endgame), there’s my favorite set of NPCs yet:
A family of the setting’s beetle-species, highly positioned in their megahive, of FMA-style haemonculi/liches. About 60 years prior to the campaign, they took advantage of a magical WMD in order to consume tens of thousands of souls. The family members are the venerable and widely respected Grandmother Comfort, her husband-in-exile Temperance (who regrets his necromantic deeds), their son General Tumult, and their (poorly-resurrected) daughter Susurrus.
A human crusade is starting up against these beetle-species hives (after that 60 years of uneasy peace), so this party (whose nominal leader is a paladin of Death) has to weigh their Abhorsen-esque duty to preserve the balance of life and death… against the fact that these liches want to help defend their nation’s vastly outnumbered armies by shackling the souls of the dead into an immortal legion of tireless defenders.