If you are referring to nootropics similar to Focalin, here are some validated testing methods:

1. Schulte Table, one of the simplest tests of attention. All you have to do is select the numbers in the table in ascending or descending order.

2. Dual-N-Back. This test assesses working memory and attention by requiring individuals to monitor a sequence of stimuli and indicate when the current stimulus matches the one presented "n" steps back.

3. Stroop Effect Test. This test measures attention and cognitive flexibility by presenting conflicting stimuli (e.g., words written in incongruent colors) and assessing the ability to inhibit automatic responses.

4. For more specialized testing, it is necessary to go to a hospital for ERP P300 component testing. ERP (Event-Related Potential) P300 component testing is a specialized cognitive assessment that measures brain responses to specific stimuli, particularly the P300 wave, which is associated with attention and cognitive processing.

The website https://humanbenchmark.com/ collects a few of these (reaction time, memory tests, typing test, aim trainer).

There is aimlabs for fps skills, but probably not relevant. Maybe some of the better online IQ tests.

Timed leetcode problems (make sure to correct for getting better with practice)

Generic typing speed + accuracy test (plenty online)

At the risk of stating the obvious: dual n-back

Minesweeper, simple sudoku (to get a bigger sample size), solving anagrams.

Depending on which games you play, go or chess puzzles?

Xeet performance

I don't know what this would look like for you, but start by pinning down which aspect of cognition (working memory, episodic memory, spatial visualization, reliability under time pressure...) you want to evaluate and narrow in on things which specifically test that. Even better if the test you settle on is something you generally struggle with, or can do iffily/unreliably well.