One of the best IQ tests I've found isn't really a test at all but is very useful for reliable concrete data instead of second hand, subjective statements. I've personally found it's useful in visual memory through gauging working memory, which does correlate to IQ. Correlation at 23 levels or higher indicates a 140IQ+ roughly, from my own personal anecdotal study I did on my friends and colleagues. Try it yourself, and take the test multiple times if needed. You will still cap out at your genetic max and it's unlikely outside of eidetic minds to be able to be personally gamed. Personal best is 23 and I've been administered in the low 140s. The reason I call it a personal study is because friends of similar IQs have been able to get 21/22+, one getting 24 and another saying they got 25 but was not seen getting 25. I believe them though. Again, you can take it as many times as you want for as many years as you want, you won't be able to improve it outside of hardware limitations such as small screens of percentage zoomed in. I've found this method extremely reliable due to this because taking IQ tests many times is what many people interested in IQ do, which nulls your real results and leaves questionable interpretations of where you could really be. If anyone wishes to reject this then feel free to provide arguments below.

https://humanbenchmark.com/tests/memory