Mine is definitely Hua Tuo, Honored Physician. I love decks with consistent value engines, and he’s an interesting commander with less than 150 decks on scryfall.
https://www.moxfield.com/decks/sR6Q8QgAuUyp7FfLG5cqPA
Note: I tend to build budget decks because I am a poor student with a lot of debt, though the only expensive upgrades I can think of would be cards like Apex Devastator .
Sideboard is filled with cards that I haven previously had in the deck. Felt that pipers like howlpack piper and Champion of Rhonas are clunky because I generally want to be casting creatures from the top of my deck, not from my hand.
I always tell people that she’s essentially the fixed Golos. She ramps and cheats spells and has a meaningful color identity.
I recently picked up a Karona, False God that looks like it could be a fun forced combat build.
I used to have a Karona deck. Lots of fun but I had a hard time keeping her alive. Plus the five color mana base can be expensive. I’m currently building a [Kharn, the Betrayer] deck that is very much in the same spirit, but seems cheaper and easier to build.
Besides the very unpopular Atraxa, praetor’s voice (/s), I love my heartless hidetsugu deck. Commander burn is … somewhat viable but delicious. Maddening hex, thermo-alchemist, guttersnipe, storm cards. It’s all there!
Evra, Halcyon Witness is so much fun!
I don’t know if he’s considered unpopular, but Chainer, Nightmare Adept is one of my all time favorite commanders, when he is leading rakdos dragons. Every card is a dragon, mentions dragons, or has dragons in the art. It is so slow and clunky, but I just love it. The main goal is to get Bladewing, The Risen onto the battlefield from the yard to cheat another dragon into play, to then bring Bladewing’s Thrall back from the dead. It’s stupid and not powerful, but it makes me feel warm and fuzzy inside.