How many types of theta are there?

Could you please enlighten me on the subject of theta? Could you clarify how many distinct varieties of theta exist? I'm quite interested in understanding the intricacies of this topic, and your expertise in the field of cryptocurrency and finance would be invaluable in answering this question. I'm hoping to gain a deeper understanding of the different types of theta and how they operate within the larger realm of cryptocurrency and financial transactions. Thank you for your time and assistance in this matter.