@BTE I didn't know which ones had already been made, and it wasn't worth the time to check individually for each one. I'm perfectly happy for you to have the main markets on this and I'm not gonna try to steal your traders; I won't link my duplicate markets in your comments.
@IsaacKing It would be nice if it was easier to see existing markets while creating new ones or if Manifold warned users before they create a duplicate.
I think duplicate markets are mostly fine, since they help reduce resolution risk and lead to artificially higher liquidity from arbitrage bots. They do cost Manifold more in unique trader bonuses though, and from an elegance standpoint I don't like how there sometimes isn't a single canonical market on a certain outcome. I'd be interested in a StackOverflow-esque duplicate-suggestion system on the market creation page, but I don't think it should be a priority.