Here is a list of all extensions published in THIS forum. You can find official extensions HERE and many other extensions HERE.
AdSense Manager by Quadric
Ajax Chat by delta
Ajax Post Rating by KeyDog
Akismet by KeyDog
bbcode_html by Abir
bbcode_table by Abir
Etherpad by Candid Dauth
Fancybox by Kushi
fancy_box2 by hoang83vu
First post by KANekT
Google Analytics by Quadric
Hide Currently Installed by KeyDog
HM Default Avatar by Himura
HM Easy BBCodes by Himura
HM Flags by Himura
Image Assistant by Quadric
IP Geolocation by Justice
KT Group Legend by Kushi
KT Mobile by Kushi
KT Newpost Highlighted by Kushi
Limit the number of topics who can see the guests by Himura
Logo by floop
Max Post View Guest by Edson Ordaz
Medal Extension by rubenwardy
Menu header by prokop
Move user to groups by KANekT
MP3 by delta
om_counter (countdown) by keeshii
om_shoutbox by keeshii
om_sort_by by keeshii
OmedOnlie-Tag by KarDo
Open Street Map by KeyDog
Portal by Daris by RimOn Ranbir
Profile Comments by Edson Ordaz
pun_censure by Dr. Deejay
pun_google_ajax_translit by Abir
pun_move_posts improved by keeshii
pun_pm_notifier by Kushi
Save post as draft by bedroom
SEO Optimizer by Quadric
show_user_location by Jesse J
Simple Image Upload by Sium
Smilies by KANekT
Spoiler by Dr. Deejay
stop_bots_record_question by Jesse J
Strikethrough text by Kaitos
subforums by prokop
Subscribe to Board by Candid Dauth
URL Checker by KeyDog
Thanks by KaNekT
Topic description by KANekT
Topics Prefixes by Edson Ordaz
Track topics in database by bedroom
WYSIWYG Editor - SCEditor by SamC