h = hide (alt+h = unhide)
L = select connected
gg = vertex slide
ctrl + r = loops
shift + d = duplicate
p = separate by
e = extrude
i = inset
ctrl + m = merge
s + y + 0 = scale by y to 0
select two vertices + j = cut
z = wireframe toggle
ctrl + i = invert (selection)
ctrl + + = increase selection?, + - = decrease?
alt + shift + s = smooth
alp + p = triangulate?
alt + j = ?
shift + r = repeat last step
ctrl + b = bevel
ctrl + m = mirror
r + yy = rotate around active edge?
ctrl + tab (+ 1,2,3) = mesh select mode (edge, vertex, face)
shift + a = add stuff
ctrl + alt + shift + c = set origin ...
alt +g = center stuff
ctrl + c = close curve
https://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Nodes/Nodes_Efficiency_Tools
ctrl + shift + LMB = Shader viewer (Easy way of prewiewing textures.)
alt + s = swap links
ctrl + T = Add Texture Setup (especially for world node)
O = Link to Output Node
Many more https://www.blenderguru.com/articles/12-useful-blender-addons-everyone-should-use