The default application launcher that provides a click-through interface for finding and launching applications. Kickoff has a search facility, allowing you to type the name of the application or its description to find it.
Lancelot is a powerful application launcher which also allows launch menus to be placed on the panel. Lancelot provides search facilities, so if you know the name of the application you don't need to find your way around the menu. Lancelot is not developed anymore[1], but there is a Plasma 5 widget inspired by it Escalibur available in the KDE Store.
KickoffMenu / KMenu is available from either the Add Widgets interface or by right-clicking on Kickoff and selecting "Switch to Classic menu style", this speedy and intuitive application launcher provides a classical hierarchical menu that is easily customized to give quick access to various useful applications and services.
There is also KRunner, which replaces the "run command" dialog, blurs the lines between task manager, desktop search, application launcher and command executor and provides a quick way to run applications or open documents among other things.
