I use http://www.quantified-mind.com/
My advice is don't get too carried away with these sorts of tests because
1) Despite test designers best intentions, all tests are learned, you get better at certain types of thinking and memory with repetition.
2) Reaction time testing will vary according to what sort of device you use ( Cellphones with touch screens may be significantly slower)
3) The last thing you want to do is create anxiety, and if you're apoe4 you are already anxious about losing your mind. From my experience my memory is twice as good when I'm in the right mood and have low inflammation, miles better after exercise and miles better when I'm relaxed with high heart rate variability.
So use these tests as a way to warm up your brain, to exercise it, do them daily, do something cognitively different every day, but mind over matter plays here, don't use them to prove to yourself that you're getting worse.
I spent a good three days ( when I had bad inflammation and headaches) beating myself up about how bad my memory was working ( I couldn't remember the names of my old employers or colleagues from a job I had 10 years ago) this included a 1 hour massage where instead of just enjoying it I spent the WHOLE time wracking my brain trying to prove to myself that I couldn't remember things.
5 days later memory seems fine.
If you do the time of day test on humanbenchmark.com you'll probably see there is enormous "variance" to how well your memory works and certainly from my experience exercise and anxiety have the greatest effect. So don't let these tests get you down, use them for what they are, exercises