csgo/cstrike15_src/hammer/editorkeys.txt

Tools:
Shift+B - block tool
Shift+C - camera tool
Shift+E	- entity tool
Shift+G	- magnify tool
Shift+V	- morph tool
Shift+S	- pointer (select/modify) tool
Shift+A - texture application tool
Shift+X - clipper tool

Clipboard/Selection:
Ctrl+C	- copy objects to clipboard (also ctrl+ins)
Ctrl+V	- paste objects from clipboard (also shift+ins)
Ctrl+X	- cut objects to clipboard (also shift+del)
Ctrl+E	- center on selection (vertex/object) in all views
Shift+Q	- clear selection
PgUp    - previous selection in "hit" list
PgDn    - next selection in "hit" list

Grid:
[       - grid lower
]       - grid higher
Shift+R	- toggle grid on/off
Shift+W - toggle snap to grid

Grouping:
Ctrl+G	- group objects
Ctrl+U	- ungroup objects

Carving/Hollowing:
Ctrl+Shift+C - carve
Ctrl+H	- hollow objects

Creating objects:
Enter       - create object drawn with block/entity tool
Alt+Shift+C - insert original prefab
Ctrl+R	    - create prefab with selected objects
Ctrl+T	    - create entity with selected objects. to add objects to
              an existing entity, select IT and the objects and hit 
		      Ctrl+T (you will be prompted.)

Other object operations:
Ctrl+B	  - snap selected objects to grid (based on boundbox)
Alt+Enter - object properties

File stuff:
Ctrl+N	- new file
Ctrl+O	- open file
Ctrl+S	- save file

Misc:
Ctrl+A	- autosize 4 views to center
Shift+Z - maximize/restore view
Ctrl+M	- transform dialog
Alt+P	- check map for errors
F9      - run map
ESC     - abort current tool mouse operation (drag/drop)

Undo/redo:
Ctrl+Z  - undo (also alt+backspace)
Ctrl+Y	- redo

2D views:
Ctrl+I	- flip vertical
Ctrl+L	- flip horizontal
TAB     - switch view types (top/side/front)
+ / -   - zoom in/out; hold CTRL to synchronize all 2D views
1 to 9  - preset zoom levels
SPACE   - hold space and leftbutton to drag view
ALT     - disable snap to grid while dragging with the mouse

Morph tool:
Ctrl+F	- split faces (morph mode)

Select tool:
CTRL    - hold ctrl and click to keep current selection
SHIFT   - hold shift when rotating to constrain rotation to
          15 degrees. hold shift when moving to create a 
		  copy of the original object at the new location.
(drag)  - hold lbutton and drag to select with a box. press
          ENTER to select objects hitting the box, or 
		  Shift+ENTER to select objects only entirely 
		  within the box.

Camera tool:
SHIFT   - create a new camera with shift (replaces old camera,
          currently.)

Clipper tool:
CTRL    - hold CTRL to move the whole clipper (both handles)
Shift+X - press Shift+X to cycle through clipper modes