Hi alexey.garmash,
Negative frames are possible to prepare a scene based information, like a pre-run of particles.
However, the Render Settings will not allow for a negative number.
If you have negative keyframes, you might select all of them and move them in one step.
If there is any Xpresso, for example, which is set up without the ability to work with this, you might re-write it.
I often get a question and the request to solve it. The problem exists because the project was tried to be solved in the wrong direction. Any solution given at that point, would cement the wrong direction and patch it with a detour solution. So my question, where negative frames come from, to begin with. What is the purpose of such? Even most compositing apps can’t deal with negative frame numbers of images sequences.
Let me know, and I hope to find the right workflow for you.
Cheers