Antonyms for the phrase "most obtained" could vary depending on the context.
For instance, the opposite of "most obtained" in terms of availability could be "least available" or "scarce." Similarly, in the context of competition or achievement, the antonyms could be "least successful," "least acquired," or "least achieved."
In some cases, the antonyms could also be phrases that indicate a lack of interest or enthusiasm. For example, "least desired," "not in demand," or "least sought after."
Overall, the antonyms for "most obtained" would vary depending on the context and the specific meaning of the phrase in that context.