If you are looking for old Final Cut Pro X releases, they will be here. I am not home right now so I will upload them later.
Some of these may be cracked versions, so use at your own risk. You will be the only responsible if something goes wrong. I installed it on my Mac and it does seem to behave normally.
Final Cut Pro X is now 10 years old, being released in 2011, so I think that some versions can be considered abandoned.
The only Final Cut Pro X version I have right now is 10.0.9, which is the last version compatible with Mountain Lion and prior versions.
Final Cut Pro X 10.0.9
From the archived App Store page
System Requirements: 2GB of RAM (4GB recommended), OpenCL-capable graphics card or Intel HD Graphics 3000 or later, 256MB of VRAM (512MB of VRAM recommended), display with 1280-by-768 resolution or higher, 2.4GB of disk space. OS X v10.6.8 or OS X v10.7.5 or OS X v10.8.3 or later. Broadcast quality monitoring requires OS X v10.7.5 or later and compatible third-party device.