LE: 14th Sept 2022 - Ubuntu 20.04 supports most of these out of the box now, with other keybinings.
Add these in :~/.config/openbox/lxde-rc.xml
or ~/.config/openbox/lubuntu-rc.xml
:
<!-- Keybindings for window tiling -->
<keybind key=C-W-Up> # FullScreen
<action name=Maximize/>
</keybind>
<keybind key=C-W-Down> # MiddleScreen
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>center</x><y>center</y><width>50%</width><height>50%</height></action>
</keybind>
<keybind key=C-W-Left> # HalfLeftScreen
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>0</x><y>0</y><height>100%</height><width>50%</width></action>
</keybind>
<keybind key=C-W-Right> # HalfRightScreen
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>-0</x><y>0</y><height>100%</height><width>50%</width></action>
</keybind>
<keybind key=C-W-1> # UpperQuarterLeft
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>0</x><y>0</y><height>50%</height><width>50%</width></action>
</keybind>
<keybind key=C-W-2> # LowerQuarterLeft
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>0</x><y>-0</y><height>50%</height><width>50%</width></action>
</keybind>
<keybind key=C-W-3> # LowerQuarterRight
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>-0</x><y>-0</y><height>50%</height><width>50%</width></action>
</keybind>
<keybind key=C-W-4> # UpperQuarterRight
<action name=UnmaximizeFull/>
<action name=MoveResizeTo><x>-0</x><y>0</y><height>50%</height><width>50%</width></action>
</keybind>
Add those inside <keyboard></keyboard>
tags. Then run: openbox --reconfigure
Adding a shortcut in lxde