I'm thinking about building an Elden Ring proxy deck (after watching this video), and this Atraxa I made would be a fun proxy commander for a poison deck.
Do you have any deck recommendations or tips for building a deck that's not too toxic to play against and suitable for casual commander?
Alternatively, a -1/-1 counter deck would also be fun if that's a thing that exists (it doesn't have to be op).
poison/infect/toxic decks are not suitable for casual commander. having played a wither deck as well I can say that you are only winning if youre staxing your opponents out of the game. not to say there isnt a place for these things, but atraxa isnt fun for a casual pod unless youre doing energy or +1/+1s or something. superfriends can be done in a less oppressive way than poison, but it still sucks to play against bc people have to focus your planeswalkers down or let you walk away with the game.
wither is the mechanic that deals damage to creatures in the form of -1 counters, read my opinion above. the best payoffs just want you to stop your opponents from having any creatures. generally any strategy that stops your opponents from playing the game their deck was built to play is felt as stax (see smokestack) and I would discourage that for casual. The issue is that its not a very strong strategy, it has trouble closing out games, it just slows them down really in my experience.
If you're building a toxic/infect deck, have you considered running [[Fynn, the Fangbearer]] instead as your commander? Can't speak for how good it is in commander as I'm only familiar with brawl, but it's a lot more thematic and hopefully won't cause the table to pull out their strongest decks right away.
As for Atraxa, you could go with a poison control/stax deck like the other commenter mentioned. Try to get a poison or two on each opponent, then proliferate them to oblivion. I don't think it would be very effective though, and it might frustrate other casual players to play against a more controlling strategy.