Recreating images from a source
According to SIAM:


  Note: Figures or tables created by someone other than the author or borrowed from a previously published source, even those created by the author him- or herself, must carry an appropriate credit line at the end of the caption. (See section 5.2.5 for additional information.)


Elsevier and IEEE have similar statements, which explicitly include the recreation of the figures.

If you have a source in mind already, it is probably safest just to cite it in the caption. However, if the form of the figure is indisputably widespread, then there is no need to cite it. I would generally follow the same fair use guidelines as does Wikipedia in such cases.

Examples I would not cite (because they are indisputably widespread):


Using circles and lines connecting them to represent a graph, G 
A Hasse Diagram to represent all possible bit combinations
The format of a UML diagram (although I would refer to it as such) 
A figure where I cannot identify an appropriate source with a reasonable amount of effort


Examples I would cite:


Any figures that I created for a previous paper ("adapted from [2]")
A figure from another paper that demonstrates a specific point, where demonstrating that same point is the reason for recreating the figure
A figure reporting data when I have not added to/modified the underlying data
Any time that I have a source in mind and I am unclear under which category it falls