I would recommend everybody to check out Third-party screenlets on screenlets.org, where I hope they will be updated and maintained.

ACPIBatteryScreenlet
A simple ACPI Battery Screenlet.

CPU Temperature with lm-sensors
Modified version of CPU Temperature Screenlet, this works with lm-sensors for CPUs that don't show temperature by ACPI.

CPU-Graph
A simple CPU graph based on CPU-Meter.

Calendar Screenlet
Name says it all :) (shows a calendar). Updated by Whise.

ComicScreenlet
ComicScreenlet lets you view online comics on your desktop. Currently it features Dilbert, Pearls before Swine and Non Sequitur, but it can easily be extended.

ConvertScreenlet
ConvertScreenlet allows you to perform various daily numerical conversions. Current version includes possibilities for converting between common number systems, file size units (B/kB/MB/GB), centimeters/inches, and temperature scales. It's easy to author new 'converters' as plugins.

DiskScreenlet
Simply show the usage of a disk.

Facebook
A screenlet to display notifications from Facebook (www.facebook.com) through their Python API.

GeneticCode
A simple widget representing the genetic code matrix.

GnomeArt Screenlet
A Screenlet that gets wallpapers from art.gnome.org website and sets them as your wallpaper image . It also shows images in the screenlet frame .You can add new images by drag&drop them into the screenlet's window area GnomeArtScreenlet by Whise aka Helder Fraga based (c) Pictureframe screenlet RYX (aka Rico Pfaus)

GraphicSystemStatus Screenlet
Shows information about your system; modified by Whise from the original Hendrik Kaju's Systemstatus Screenlet.

Horoscope
Displays today's horoscope forecast (from astrology.yahoo.com).

MyRssScreenlet 0.1
Screenlet permitting to view some sindicated content in RSS

NowPlaying Screenlet
A screenlet to show what's currently playing (and probably eventually control it). Originally by magicrobotmonkey, updated by Whise. So far works with Amarok, Banshee, Exaile, Listen and Rhythmbox.

OrlojScreenlet
An astronomical clock , modeled after the Prague Orloj. It displays local time, in 24h format, local sidereal time , an approximation of the position of the sun and the moon in the zodiac, approximate local sunrise /sunset, and the phases of the moon.

RDesktop
A widget for easy access to remote desktop configurations. RDesktop is configured once and applied to all connections.

RandomPassword Screenlet
A Password generator Screenlet - Hit enter or tab for a new password , the passwords get auto stored in the clipboard; by Helder Fraga aka Whise (c) 2007

Rss Screenlet
RSS reader. Updated by Whise.

Sidebar Screenlet
Posted July 26th, 2007 by Whise; this is a screenlet to mimic the vista sidebar (eye candy only) it doesn't do anything else.

Stocks
Display stock changes

Systemstatus Screenlet
The original Hendrik Kaju's Systemstatus Screenlet that shows your system's status, updated by Whise

Temperature2
A themeable temperature meter based on TemperatureScreenlet by fader (aka Ronald McCollam).

TemperatureScreenlet
A simple CPU temperature gauge.

TorrentSearch Screenlet
A screenlet by Whise that searches the most popular torrent sites, based on (c) Patrik Kullman 2007 WebsearchScreenlet.

WatchScreenlet
Allows the user to enter a shell command which executes periodically on a set interval displaying the output. Useful for fortune, system status information &c. No fancy graphics just stdout. Default setting to memory free, cpu frequency and number of users logged so you can tell when you're not alone!

Weather Screenlet
Shows the weather for your location. It has multiple display modes (Mini, Normal and Extended Forecast). Retrieves data from www.weather.com. Updated by Whise.

WebSearch
A screenlet for easy web searches on Digg, Delicious, Google, IMDb, Wikipedia or Yahoo. Easy to add more (just one line of code and an icon).

Wireless
A screenlet to display the current link quality and ESSID.

Word of the Day
A screenlet to display the word of the day from dictionary.com, with a link (info-button) that opens up a more complete desciption in the browser if clicked.