A minyan factory is a place that has almost constant minyanim throughout the day starting from shachris untill maariv.
Many chassideshe batei medrashem are basically minyen factorys but some examples of minyen factories are are:
Shomer Shabbes in boro park
Landaus in flatbush
Sheiners in monsey
Hachaim Vshalom in the 5 towns
and then of course in Erets Yisroel therse many such as “shteeblech”.
