Short: Maybe a Gnome shell like dashboard for Xfce
Longer: xfdashboard provides a GNOME shell dashboard like interface for use with Xfce desktop. It can be configured to run to any keyboard shortcut and when executed provides an overview of applications currently open enabling the user to switch between different applications. The search feature works like Xfce's app finder which makes it convenient to search for and start applications.
You can find a quick'n'dirty guide to xfdashboard at this link.
Documentation for theming is here.
All settings stored in Xfconf by xfdashboard are documented here.
The latest stable version is version 0.6.1 released at 2016-12-22.
You can download the source tarball using the following links:
For older releases including development versions look at the release archive at the following link.
The latest development version is version 0.7.5 released at 2018-08-09.
You can download the source tarball using the following links:
For older development releases or stable releases look at the release archive.
The latest development version is hosted on Xfce Git. You can browse it using the web interface at the following URL: http://git.xfce.org/apps/xfdashboard/
Here you find the documentation for theming and settings of the latest development version.
The FAQ for xfdashboard can be found here.