favorite phono cartridge

Of course it's a question of personal taste, but since that's what the OP asked for, my choice would be (and is) ZYX UNIverse II-X-SB, low output.

I agree, there can be no definitive "best". There can be only a consensus "best". There certainly can be an individual's "best". "Best" is always a moving target. Quite often there are new bests. Positively subjective. Having said that, a "best" that is determined by design, material, workmanship, imagination, functionality and/or a true step forward, a revolutionary change, are at least one of the very "best". This is true no matter the system, environment, taste or other personnel feelings. Yes "best" is subjective. But all great(best) things like art, music, poetry, novels and yes audio equipment are arrive through time and consensus.
I have not heard every cart(ZYX) out there but from what I have heard,
mine are;
MC type
Lyra atlas
Ortofon anna
Dynavector DRT XV-1s
Clearaudio goldfinger
Benz Micro LPs

MM type
Grace f9 / soundsmith Ruby OCL stylus

*I have heard several other cartridges that do not make it on my list.*

Ortofon A-90 still hangin in there.

Lewm, at present I own the ortofon anna only. I have owned about 15 different cartridges. Many I was happy to get rid of. Some made me nervous(atlas, gold finger, XV1-s). Others just time for a change(moving target). All part of the experimate. If there can only be one, at present I would stand by my listed order. Although, I would probably stick with anna. As I said, the atlas makes me nervous.

Shure V15 type IV with Ed Saunders stylus.