I released a few days ago on my site 13 plugins converted for use with Immunity Debugger 1.8x.
Most are converted from OllyDbg plugins, and some were original Immunity Debugger plugin format.
All plugins were converted with my FixPlugins tool.. Find them (and more!) here
Immunity Debugger PDK v1.03 - A multi-debugger aware PDK that will enable the same plugin to be used with old ImmDbg, New ImmDbg (v1.8x+), and OllyDbg (and patched versions). No patching is needed to make it work on EG ImmDbg v1.73, OllySND or OllyDRX, in fact the plugin can be in a shared plugin folder for all three!
Get it Here
PluginFix v1.01 - Conversion tool for old ImmDbg plugins, and OllyDbg plugins, to make them work with newer v1.8x ImmDbg Plugin changes. This process requires altering of the Imports and Exports of a plugin to allow it to:
A) Be loaded by ImmDbg v1.8x, by removing implicit Imports to OllyDbg or old ImmDbg.
B) Fix the Exports to be recognised by ImmDbg as a valid plugin.
Get it Here
More detailed information will be found if you click the links.