After my grandfather was diagnosed with Parkinson's in 2003-2004 I saw this first hand and consequently set about solving the problem in software. SteadyMouse was born.

The software contains both an anti-tremor motion rejection algorithm to keep things stable, and an accidental click blocking mechanism to only let through intended clicks.

The last two years were spent on a massive upgrade for a commercial version (in addition to the original free version).

Here's a gif of the filtering in action: https://twitter.com/steadymouse/status/890794753637326848

The main site is here: https://www.steadymouse.com/