Interactive Simplifier
The tool is an interactive version of Simplify Vector, providing the same settings but allowing to immediately check the outcome of the simplification (as soon as it is calculated) and if deemed fine the outcome can be exported back to QGIS project.
The only difference is that partial generalization is based on active selection on the layer (instead of attribute). User can select if selected features should be generalized (leaving the rest intact) or if the selected features should remain intact and all other features should be generalized.