Such a person could be called an ascetic. You might also used the word eremite, the root of the word hermit.
A person who practices abstinence as a spiritual discipline is commonly referred to as an ascetic.
The spiritual discipline of Japa involves repetitive meditation of mantra. Mantra meaning name of a divine power. Sometimes this task involves only one person alone and can also be preformed as a group. Sometimes props such as beads are included.
A bhakta is a person who practises bhakti - a person who is devoted to God in Hinduism.
A calligrapher is a person who practises calligraphy.
An agriculturist is a professional who specializes in the study and practice of agriculture, including crop production, soil management, and animal husbandry. They work to improve agricultural practices, increase crop yields, and promote sustainability in farming.
An agriculturist is a person who practises agriculture - such as a farmer or a gardener.
An assyriologist is a person who practises Assyriology, the study of ancient Assyria.
An allopath is a person who practises allopathy, the study of traditional medicine.
An agaricologist is a person who studies or practises agaricology - the study of fungi.
Abstinence - is the act of a person choosing not to participate in a certain activity. This can be something like... not drinking alcohol, or not having intercourse before marriage.
Allopath
An arachnomancer is a person who practises arachnomancy, the study of the appearance and behaviour of spiders.