I just installed lxde to boot into when laptop is using battery, but I really miss at least a simple search feature, I am used to Unity so I find myself losing too much time navigating on the menus, given that the LXDE menu is just a list with a basic categorization. I would prefer to avoid creating shortcuts everywhere if possible.
Forget about that, there's nothing like that for the LXDE menu, use Synapse.
Install it from the terminal:
sudo apt-get install synapse
Synapse review with screenshots http://www.omgubuntu.co.uk/2010/11/synapse-gnome-do-launcher-app-review-ubuntu
The correct, fancy name for it is semantic launcher BTW :)
Other related stuff:
Zeitgeist - indexing tool used by Synapse
Gnome Do - another launcher similar to Synapse, older
Kupfer provides a simple menu searcher activated from a global keyboard shortcut.
By default you show Kupfer using the global keyboard shortcut Ctrl+Space.
https://kupferlauncher.github.io/
A quick video review can be found here.
XFCE provides an excellent app finder. You can install it with
Lubuntu 18.10 with LXQt desktop has two search tools by default:
lxqt-runner
)Their shortcuts are configurable, including the "Super" key; under Preferences>LXQt Settings>LXQt Configurations settings>Shortcut keys.