This topic is simply a list of some of the important StraightLine Mechanisms. Not Mechanism Synthesis.
They are included for reference.
A.  StraightLine Mechanisms with PinJoints only 
In each image, the PinJoints are given a letter. The input joint is at A. You can scale each mechanism from the relative lengths of each Part. The Point at letter 'K' is the coupler point and it moves in a straightline.
B.  StraightLine Mechanisms with Pin and SlideJoints 
There are also straightline mechanisms that have a SlideJoint! This might seem ridiculous as why produce a straightline with a mechanism when it should be easy to use the linear slider directly!
However, when the slidejoint moves only a short distance as compared to the distance the coupler point moves, then they are useful.
Also, they are sometimes useful to change the straightline motion to a different direction.
See YouTube video http://youtu.be/JlGKZCus6iw 

Watt StraightLine Watt  Popup AB=BC=CD=L AD(δx) = 2L AD(δy)=L BK=CK=0.5L 

Roberts StrainLine Roberts Popup AB=CD=AD=BK=CK=2L BC=L


Tchebycheff & Translating AB=CD=2.5L AD=2L BC=L BK=0.5L FK is the Translating Part. CE=EF=1.25L ; FK=L 

Modified Scott Russell AB*BC=BK2 CD= longer the better 

Hoeken AC=L AB=2L BD=CD=2.5L D.K=2.5L


Peaucellier 1  EXACT STRAIGHT LINE AD=DC=1L AB=AE=2.5L BC=BK=CE=EK=1.2L 

Peaucellier 2  Inverse  EXACT STRAIGHT LINE AD=AB=1L DC=DE=1.25L BC=CK=BE=EK=1.5L 

Kempe 1 AB=BC=DC=AD=2L AE=EC=EK=1L CF=FK=0.5L 

Kempe 2 AB=DC=BE=CF=CK=1L AD=BC=EF=AK=2L GK=FG=0.5L Notice that four Parts are Blue  this means that MechDesigner solves their postilions, but not with closed loop equations. 

Hart AB=AD=3L BC=DC=6L AE=L EG=4L DF=GF=FK=2L 

Hart  EXACT STRAIGHT LINE AB=AD=1L DC=DE=1.4L BC=BF=EK=3L EG=6L FG=2.8 

Translating Table  or Engineers Table 
Scott RussellAB=BC=BK CD= ∞ (D @ infinity Y) 