Single most important criteria: Have a logo that is - even without the font/writing recognizable and not usable for any other podcast.
We have recently launched our Podcast for the German Market, which is called "Die Dominieren statt Kämpfen Show" which means "The Dominate instead of Struggle/Fight Show" and we are looking for a Logo that we can use for our Podcast as well as for the website - please see attached pdf for examples of logos we love. You can also see the logo of Dr. Julian Hosp, the moderator of the show (here we've incorporated his name and his background as doctor).