So I did a bit of research and came up with the top 5 most expensive Commander cards
How about MTG porn
Dave & Adams, a US-based TCG vendor that traditionally deals in sports collectibles but also sells MTG, Pokmon and Yu-Gi-Oh

Rarity: R Cost: 5BB Card Type: Sorcery Artist: Bram Sels Name: Kindred Dominance Finish: Foil Card Number: 0515 Set Name: Commander Masters Related Products Avatar Aang // Aang, Master of Elements - Raised Foil Avatar: The Last Airbender M/NM, English Limit 1 M/NM, EnglishLimit 1 M/NM, English Limit 1 Latias & Latios GX - 170/181 - Alternate Full Art - Ultra Rare SM9 Team Up M/NM Limit 14 M/NMLimit 14 M/NM Limit 14 Buzz Lightyear - Jungle Ranger - 241/204 - Iconic - Holofoil DLC12 Wilds Unknown M/NM Limit 5 M/NMLimit 5 M/NM Limit 5 Leonardo, Sewer Samurai - Foil - Borderless - Gold-Stamped Signature Teenage Mutant Ninja Turtles M/NM, English Limit 1 M/NM, EnglishLimit 1 M/NM, English Limit 1 Umbreon VMAX - 215/203 - Secret Rare SS07 Evolving Skies M/NM Limit 5 M/NMLimit 5 M/NM Limit 5 Raphael, Ninja Destroyer - Foil - Borderless - Gold-Stamped Signature Teenage Mutant Ninja Turtles M/NM, English Limit 1 M/NM, EnglishLimit 1 M/NM, English Limit 1 Michelangelo, Improviser - Foil - Borderless - Gold-Stamped Signature Teenage Mutant Ninja Turtles M/NM, English Limit 1 M/NM, EnglishLimit 1 M/NM, English Limit 1 Gengar & Mimikyu GX - 165/181 - Alternate Full Art - Ultra Rare SM9 Team Up M/NM Limit 14 M/NMLimit 14 M/NM Limit 14 Sol Ring (0408) Commander: The Lord of the Rings: Tales of Middle-Earth M/NM, English Limit 17 M/NM, EnglishLimit 17 M/NM, English Limit 17 Donatello, Mutant Mechanic - Foil - Borderless - Gold-Stamped Signature Teenage Mutant Ninja Turtles M/NM, English Limit 1 M/NM, EnglishLimit 1 M/NM, English Limit 1

With 202 choices of Human Knight, we have a great deal of room to play with
There will, of course, be some light spoilers of the prologue section in todays article, though nothing much more than what trailers and press releases have revealed thus far