1. Add a line
Ctl+Alt+Up/Down command: select_lines args: forward [up:false, down:true]
2. Split selection into lines
Ctrl+Shift+L for a selected block command: split_selection_into_lines
3. Add next occurrence
Ctrl+D command: find_under_expand
4. Find all occurrences
Alt+F3 command: find_all_under
5. Undo add line/occurrence
Ctrl+U command: soft_undo
6. Add with mouse
Ctrl+Mouse click source: Default.sublime-mousemap
7. Add/Remove custom blocks to selection
Ctrl+DragSelect - add to selection Alt+DragSelect - remove from selection source: Default.sublime-mousemap
8. Create/Add/Remove selection by columns
Shift+MouseRight+DragSelect - create selection Ctrl+Shift+MouseRight+DragSelect - add to selection Alt+Shift+MouseRight+DragSelect - remove from selection [Ctrl|Alt]+MouseWheel+DragSelect - the same actions source: Default.sublime-mousemap