By coincidence, I stumbled upon an article about bias in coin tosses. It reminded me about this topic, hence the 10 month bump.
TL;DR: if you start a coin toll with heads up, there's a 50.8% chance you'll end up with heads.
This is the important part:
Delving into the data further, they found that coin tosses are highly variable between people, with some showing a strong same-side bias and others having none at all – coin tosses may come down (ever so slightly) to the tosser.
Some people have the bias and others don't.
It makes me think: What would a device with a spring to launch the coin do? It would almost certainly eliminate all bias in coin tosses - provided it is engineered properly - and it could even be made into a wearable on your hand that you can use to emulate a traditional coin toss.