First of all, good sir, I took time out of my day to answer your question because you needed help. I apologize that what I responded with was not relevant to that which you were looking for.
Second of all, how could anyone possibly deduce the exact pinpoint desire of your query by the simple two sentences of "Does anyone have any flat seeds? I'm still hunting for some"? The only official terminology within Minecraft that defines any world as "flat" are the flat worlds, which you create by enabling the option. Again, I apologize for not understanding your shorthand lingo, but it appears as if I have indeed misplaced my information as it does not apply to your wonderings.
Now it's my turn to ask to you a question. Why is it, upon realizing my information was not sufficient enough to complete your quest for "flat seeds" as you put it, instead of clarifying your point and aiding me to respond with perhaps better information for you, you decide to personally attack myself, by insulting my intelligence? Are you aware that the ideology of psychic is entirely false? A mere hypothesis? Not only could I not read your mind to understand what you meant - nobody on planet Earth could. Does that make the remaining 7 billion people that populate our planet - including your friends, family, neighbors, etc. also of lower intelligence than you?
Good luck attempting to find help or getting anyone to respond to you now, because you have just made yourself look very, very terrible.
And I'm going to assume by the picture of the game Roblox in your signature that you are probably a minor; no older than seventeen.