Plotting

Explanation of tables
*green Function exists in octave 2.0.x
Noted incompatibilities and missing features
+yellow Function exists in matcompat
Author and home for the function.
?orange Function doesn't exist
Explanation of what you can do instead.
xred Function doesn't exist, and no work-around

Line plots
*plot
+plot3
Paul Kienzle
*loglog
*semilogx
*semilogy
*polar
xplotyy
?errorbar
Teemu Ikonen announces errorbar support, though not fully compatible.
xscatter
xplotmatrix
+stem
Paul Kienzle
xstem3
*stairs
xcomet
xfeather

Business graphs
+pie
Daniel Heiserer.
xpie3
xarea
*bar
xbarh
xbar3
xbar3h
xribbon
xpareto
+fill
Daniel Heiserer has a hack for gnuplot. See the archives for a better way (if you are willing to patch gnuplot).

Contour plots
+contour
parameter order changed by Paul Kienzle to correspond to Matlab
xcontourf
xcontour3
xclabel
?pcolor
use imagesc; Jean-Marc Valin has an OpenGL-based pcolor application.

Surface plots
*mesh
+surf
Paul Kienzle
xcomet3
+quiver
Roberto Almeida
+meshc
faked by Paul Kienzle
xmeshz
xscatter3
+surfc
faked by Paul Kienzle
xtrisurf
?trimesh
Kai Habel; part of his geometry toolbox
xwaterfall
+fill3
Based on ??

Volume plots
xisosurface
xisonormals
xisocaps
xcontourslice
xslice
xstreamline
xstream3
xstream2
xquiver3
xconeplot
xsubvolume
xreducevolume
xsmooth3

Function and expression plotters
xezpolar
xezplot
xezcontour
xezcontourf
xezmesh
xezmeshc
xezsurf
xezsurfc
xezgraph3
xezplot3
xfplot