Body Voltage measurements at: 2:55 and 6:27

Gigahertz ME3851A:
Still one of the best meters on the market at this date, even with it's flaws
(other EMF meters usually have much worse flaws).
https://gigahertz-solutions.com/Measurement/Low-Frequency

Gigahertz ME3830B (I would recommend this one as an entry-level model, because it goes up to 100kHz, which is important for EMF sensitive people):
https://gigahertz-solutions.com/Measurement/Low-Frequency/ME3830B

BK Precision 2709B:
For checking body voltage (what we EHS people need) and most basic electric and electronic measurements this BK Precision seems pretty good, just know that it has flaws like all multimeters in this price range. It's not a professional tool like a 300$ Fluke is (but such a Pro meter is over the top for EHS people, not really needed).
Note that a too cheap multimeter won't work for measuring body voltage ! At the date of this video most multimeters of around 60$ should work though.
https://www.tequipment.net/BK2709B.html

Cornet ED88T:
This device can be very useful for magnetic fields and RF (like WiFi).
https://www.radmeters.com/Cornet-ED88TPlus5G2.html

Building Biology Guidelines:
https://www.baubiologie.de/downloads/building-biology-guidelines-english.pdf

https://www.slt.co/Downloads/Education/EMF-Exposure-Guidelines-For-Sleeping-Areas.pdf