Although I do not regard all as required, I list notifications which can transmit by event system of Q2A. It may be in others.
1. Post
1.1 Question (Q2A event : q_post)
1.1.1 Someone asked question.
1.1.2 Someone asked question that belongs to category followed by me.
1.1.3 Someone asked question that belongs to tag followed by me.
1.1.4 User followed by me asked question.
1.1.5 User followed by me asked question that belongs to category followed by me.
1.1.6 User followed by me asked question that belongs to tag followed by me.
1.2 Answer (Q2A event : a_post)
1.2.1 Someone answered question.
1.2.2 Someone answered question that belongs to category followed by me.
1.2.3 Someone answered question that belongs to tag followed by me.
1.2.4 Someone answered question followed by me.
1.2.5 User followed by me answered question.
1.2.6 User followed by me answered question that belongs to category followed by me.
1.2.7 User followed by me answered question that belongs to tag followed by me.
1.2.8 User followed by me answered question followed by me.
1.3 Comment (Q2A event : c_post)
1.3.1 Someone commented on question.
1.3.2 Someone commented on answer of question.
1.3.3 Someone commented on question that belongs to category followed by me.
1.3.4 Someone commented on answer of question that belongs to category followed by me.
1.3.5 Someone commented on question that belongs to tag followed by me.
1.3.6 Someone commented on answer of question that belongs to tag followed by me.
1.3.7 Someone commented on question followed by me.
1.3.8 Someone commented on answer of question followed by me.
1.3.9 User followed by me commented on question.
1.3.10 User followed by me commented on answer of question.
1.3.11 User followed by me commented on question that belongs to category followed by me.
1.3.12 User followed by me commented on answer of question that belongs to category followed by me.
1.3.13 User followed by me commented on question that belongs to tag followed by me.
1.3.14 User followed by me commented on answer of question that belongs to tag followed by me.
1.3.15 User followed by me commented on question followed by me.
1.3.16 User followed by me commented on answer of question followed by me.
2. Up Vote
2.1 Question (Q2A event : q_vote_up)
2.1.1 Someone voted my question.
2.1.2 User followed by me voted my question.
2.2 Answer (Q2A event : a_vote_up)
2.2.1 Someone voted my answer.
2.2.2 User followed by me voted my answer.
3. Follow (Favorite)
3.1 User (Q2A event : u_favorite)
3.1.1 Someone followed anyone.
3.1.2 Someone followed me.
3.1.3 User followed by me followed anyone.
3.1.4 User followed by me followed me.
3.2 Category (Q2A event : cat_favorite)
3.2.1 Someone followed category.
3.2.2 Someone followed category followed by me.
3.2.3 User followed by me followed category.
3.2.4 User followed by me followed category followed by me.
3.3 Tag (Q2A event : tag_favorite)
3.3.1 Someone followed tag.
3.3.2 Someone followed tag followed by me.
3.3.3 User followed by me followed tag.
3.3.4 User followed by me followed tag followed by me.
3.4 Question (Q2A event : q_favorite)
3.4.1 Someone followed question.
3.4.2 Someone followed question followed by me.
3.4.3 User followed by me followed question.
3.4.4 User followed by me followed question followed by me.
----- Plugin Option -----
- Enable/Disable of plugin.
- Setting page only for this plugin.
- Enable/Disable according to notification type on admin page.
- Enable/Disable according to notification type on user account page.