We are experiencing issues with ANR adding too many neighbors, including distant ones. We are unable to find a way to control the excessive number of neighbors.
Any advice?
Vendor: Huawei
Disable it.
Any other solutions?
Is it possible to automatically disable handovers for redundant neighbor relations?
Swap to Ericsson. 
How about applying a reasonable tilt to the cells?
I believe there is a limitation of a maximum of 256 neighbors in OSS, but no cell should ideally have more than 100-120 neighbors.