As in the original terminology and meaning of an "Involuntary Celebate"? Those that have issues communicating and forming relationships with members of their attracted sex mainly due to social anxiety and awkwardness? Then yes.
If you mean the co-opted term that typically men (and not uncommonly women) use nowadays as means of expressing misogynistic and hatred views towards the opposite sex as a veil to shift blame for their own shortcomings? No, I have not, nor would I associated with those types of people.
A long time ago I worked with a guy who I would describe as a 'Incel'. Mid 20s, tall and good looking, came from a great family, good job, drove a nice car, had a decent personality with hobbies and interests, and could hold a good conversation. However, when it came to speaking with women, he was a bumbling buffoon. He genuinely had severe anxiety when speaking to women he was attracted to and the awkwardness always led to him being passed by. I'm no Casanova myself, but I never ran into much issue in the dating department... We'd often chat during lunch/smoke breaks and he'd ask advice on how to be more relaxed and less awkward around women. Never once did he blame them for his own issues and actively tried to work on himself. Last I heard he was married with kids. That to me is what a quintessential 'incel' is/was, not the abomination of what the term means today.
I just think some people have too much time on their hands and use it the wrong way...
