A lot of supplements include vitamin B6. As others have said, magnesium and multivitamins are among the most likely to include way too much.

In May I had a blood test to see if I was deficient in vitamin B6. The test came back with a pathology warning that I was at high risk for peripheral neuropathy with B6 level at 720 nmol/L - normal range is 20 - 190 nmol/L. I was told to check supplements, especially magnesium. The magnesium I'd been taking for over 10yrs included 60mg of B6, a toxic dose when taken daily, as I was. The recommended daily dose is 1-3mg.

I immediately switched magnesium brands to one with no B6 and my latest blood test is B6: 80 nmol/L. Back to normal. No wonder I had years of unexplained intermittent hand and feet numbness.

Have you checked the ingredients list for every one of your supplements for B6 (pyridoxine), starting with the magnesium? You may be surprised to find it in one or more of them.