I would take your question to mean people who are fluent in Coptic (spoken and written), for example C1 in Common European Framework of Reference for Languages (CEFR).
I am aware of the families of Pisenty Rizkalla, there is an interesting video of one of the speakers named Toutmos Rizkalla, there are also families like Fr Pigol Bassili, and families like Maurice AbdelMessih. These consider themselves natives/bilingual speakers, albeit some argue that it is a pidgin form of the language that is used.
Dr Kamal F. Ishaq hosted a monthly meeting for Coptic language speakers for many years. It gathered between 6-18 people. A few could speak fluently at that time. The most fluent person that I have seen was Dr Nabil Mikhail Markos. Dr Kamal F. Ishaq also speaks very well.
Otherwise, George Sedhom of Akhmim speaks fluent Coptic, Amadou Attiya and many others speak fluently.
I cannot quantify the number of speakers, as they are not in the same circle.