Vertex crease

Does this exist in Blender? I can’t find it.

No, it does not.

Vertex Crease should be in when OpenSubDiv is finally integrated into Blender, as you can see in that video of OpenSubDiv showcased in modo, vertex crease can be done :

Now that said, with extrusion there’s a trick to get some vertex crease-like visual in Blender
Select your vertex :
http://i.imgur.com/0vYGwMP.jpg

Press E
http://i.imgur.com/jvNiUDa.jpg

Then move that vertex to control the creasing in the way you want
http://i.imgur.com/kS6omZ8.jpg

http://i.imgur.com/rZnz4bI.jpg

Cool and handy)