What is your favorite unpopular commander?
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 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.
I built Karona as an enchantress control deck. The goal was to pillow-fort myself, keep everything else off the board, and then MLD before a Solemnity/Decree of Silence combo. At that point, no one has anything and all they can do is hit each other with my commander.
I only played it twice, because it was deemed too mean.