ah luff deez gais.

there are absolutely tons of modules/extensions/plugins for expression engine.  the ones i’ve found most useful are these:

modules:

solspace freeform: Freeform allows you to create simple forms on your site to collect information from your users. Postings to your forms are recorded and organized in your EE database as well as optionally mailed to the notification emails you supply. You can receive attachments from submitters and have those attachments stored in your database as well as mailed back out as attachments to admins or the submitting user

linklist: The Link List module organizes your links to other websites. With the Link List module, you can add/edit/delete links, display links on any webpage.

low nospam: Low NoSpam will check comments to see if they’re considered to be spam by the chosen service, either Akismet or TypePad AntiSpam. It can optionally also check incoming trackbacks, gallery comments, forum posts and wiki articles. Caught (gallery) comments will be set to Closed for further moderation. Caught trackbacks, forum posts and wiki articles will be discarded, since these do not have a native moderating system in EE.

solspace tag: The Tag Module allows you and your users to add Tags to weblog and/or photo gallery entries. It’s a very powerful module that allows you to create several different features in your templates using robust functions. You can show Tags that belong to an entry, view all entries that are Tagged with a specified Tag, show related entries based on shared Tags, and build a Tag “Cloud” to show and weigh all Tags in system. Additionally, your members can also subscribe to Tags, and view entries based on Tags they’ve subscribed to.

extensions:

lg twitter: LG Twitter is a Multi-Site Manager compatible extension that allows you to post Tweets to Twitter.com from your ExpressionEngine control panel. Tweets can be posted through a Twitter tab which is added to the publish / edit form or through the “Quick Tweet” bar.

plug ins:

links mentioned: Extract and display links from your entries.

randomizer plus: Allows you to show random content in your template. The “Plus” feature is that you can modify the random content in your template instead of in the plugin file, and can use any separator for the items.

md eexcerpt: Creates excerpts after stripping out tags.

trunchtml: Truncates HTML/Text after the specified number of characters.

weather icon: Shows Current Weather Conditions by querying the NOAA website.

wimpy mp3 player and wimpy player: An MP3 player jukebox for your ExpressionEngine site.

i should, also, include two tools that i make use of, but that aren’t specifically for expression engine.  they can be used on any site:

share this - Website publishers can embed the free ShareThis button to increase traffic to their site. Sharing your site’s content to contacts on Facebook, MySpace, AIM, email and text messaging ensures sharing with ease.

sphere - Sphere connects your current articles to contextually relevant content from your archives as well as from Blog Posts, Media Articles, Video, Photos, and Ads from across the Web.

i’ve previously listed my favorite web design tools, my favorite firefox addons, so now my favorite sites about web design:

psd tuts - “Psdtuts+ is a blog/Photoshop site made to house and showcase some of the best Photoshop tutorials around. We publish tutorials that not only produce great graphics and effects, but explain the techniques behind them in a friendly, approachable manner.”  don’t miss the rest of the tuts network of sites, either: net tuts, vector tuts, audio tuts, and cg tuts.

six revisions - “Six Revisions is a weblog that provides practical, useful information for the modern, standards-compliant web designer and web developer. It seeks to present exceptional, noteworthy tips, tutorials, and resources that the modern web professional will appreciate. You’ll find a variety of content from tools that can speed up your workflow processes to showcases of beautiful designs for inspiration and tutorials on JavaScript frameworks like jQuery and MooTools.”

web designer wall - “A wall of design ideas, web trends, and tutorials.”

css globe - “...your daily source of css news.”

css play - experimenting with css

noupe - “NOUPE passionately delivers stylish and dynamic news for designers and web-developers on all subjects of design, ranging from; CSS, Ajax, Javascript, web design, graphics, typography, advertising & much more.”

smashing magazine - “Smashing Magazine delivers useful and innovative information to Web designers and developers. Our aim is to inform our readers about the latest trends and techniques in Web development. We try to convince you not with the quantity but with the quality of the information we present.”

sharebrain - “a web designer’s magazine for knowledge, resources, and inspiration”

design reviver - “Here you will find useful tutorials, free downloads, sources of inspiration, and articles covering a wide range of web design related topics.”

there’s a bit of overlap here and there, but each is handy for specific purposes!

colorzilla - Advanced Eyedropper, ColorPicker, Page Zoomer and other colorful goodies.  With ColorZilla you can get a color reading from any point in your browser, quickly adjust this color and paste it into another program. You can Zoom the page you are viewing and measure distances between any two points on the page. The built-in palette browser allows choosing colors from pre-defined color sets and saving the most used colors in custom palettes. DOM spying features allow getting various information about DOM elements quickly and easily.

dom inspector - DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM hierarchy can be navigated using a two-paned window that allows for a variety of different views on the document and all nodes within.

dummy lipsum generator - Generate “Lorem Ipsum” dummy text (from http://www.lipsum.com).

firebug - Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page…

fireshot - FireShot is a Firefox extension that creates screenshots of web pages (entirely or just visible part).  Unlike other extensions, this plugin provides a set of editing and annotation tools, which let users quickly modify web captures and insert text annotations and graphical annotations. Such functionality will be especially useful for web designers, testers and content reviewers.

ghostery - Ghostery Watches the Web Sites that are Watching You.  Find out how web sites are watching you across every page on the web with Ghostery. Ghostery alerts you when you visit a web site that has web bugs on it. Web bugs are hidden scripts that track your behavior and are used by the sites you visit to understand their own audience.

i.e. netrenderer - Render the current page with IE NetRenderer

link checker - Check the validity of links on any webpage

live http headers - View HTTP headers of a page and while browsing.

lori (life-of-request info) - ‘lori’ can tell you how long it takes to load a page. Useful for web developers who are working on profiling, optimizing a web site

measure it - Draw out a ruler to get the pixel width and height of any elements on a webpage

screengrab - Screengrab! saves webpages as images…  It will capture what you can see in the window, the entire page, just a selection, a particular frame… basically it saves webpages as images - either to a file, or to the clipboard.

seo quake - Seoquake is a Mozilla Firefox SEO extension aimed primarily at helping web masters who deal with search engine optimization(SEO) and internet promotion of web sites. Seoquake allows to obtain and investigate many important SEO parameters of the internet…

total validator - Perform multiple validations and take screen shots in one go. This 5-in-1 validator works with external, internal, or local web pages using the Total Validator service or local copy of the desktop tool…

web developer - Adds a menu and a toolbar with various web developer tools

user agent switcher - The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of the browser

a short collection of web-design tools that i like - some i’ve used, some are handy to have just in case!

icon drawer - free & stock icons

patterific - free seamless patterns

bg patterns - free tool to create tiled backgrounds

repper - create your own patterns

960 grid system - streamline web development workflow by providing commonly used dimensions, based on a width of 960 pixels

dummy text generator - lorem ipsum generator

tabs generator - tab menu generator

copysense - reference for character entities

camen design’s video for everybody - code that embeds a video into a website

scrnshots - scrnshots, share your inspiration

update: missed one! colour lovers - colour trends + palettes