One of the first commanders that came to mind when I saw this was Rakdos, Lord of Riots
Rionya excels at copying non-legendary creatures, first and foremost, and so having an extra copy of Akki Battle Squad to trigger from your attacking modified creatures every combat means youre set
(24 of these cards are also available as Quarter-Century Secret Rares and 1 special card is ONLY available as a Quarter-Century Secret Rare!)
Troll, for example, can be an easy plant for a reanimator deck, putting itself in your graveyard and smoothing your mana in the process
How long does it take to become Legendary? If you've Dueled competitively in 2025, you'll know that there's nothing quite like the powerful Ritualbased strategy, "Mitsurugi", and it's less than a year old, debuting in January's Supreme Darkness