Note: a few of the [obsolete] styles have screenshots posted with them that have nothing to do with the style itself but are being referenced in the descriptions of some other styles (just wanted to keep all style-related images "onsite").

Demo styles:
http://freestyler.ws/style/125296/firefox-w-side-tabs-vertical-toolbar-customized (06Oct2012)

Current styles:

http://freestyler.ws/style/125268/fx-header-like-slacker-radio-persona
http://freestyler.ws/style/122908/fx-active-tab-like-firefox-button
http://freestyler.ws/style/125258/fx-bookmarks-aligned-center
http://freestyler.ws/style/124538/fx-browser-borders-in-css
http://freestyler.ws/style/123541/fx-menus-highlight-flatstylish
userstyles's userstyles's Black Rock Shooter (version 2.0)
http://freestyler.ws/style/124943/orion-editor-comment-quote-highlighting
http://freestyler.ws/style/125298/side-tabs-customized
http://freestyler.ws/style/21251/slacker-radio-just-the-player
http://freestyler.ws/style/15567/titantv-just-the-grid
http://freestyler.ws/style/29797/userscripts-org-front-page-news-icons-24x24
http://freestyler.ws/style/30361/userscripts-org-front-page-news-links-format
http://freestyler.ws/style/40322/userstyles-org-show-code-display
http://freestyler.ws/style/15438/userstyles-org-pagination-buttons-green
http://freestyler.ws/style/64656/usoforum-glowydark
http://freestyler.ws/style/67922/usoforum-simpleblue
http://freestyler.ws/style/68264/usomain-ad-fixed
http://freestyler.ws/style/63695/usomain-simplescrollbars
http://freestyler.ws/style/63377/usomain-simplestyle

Obsolete styles:

http://freestyler.ws/style/124094/back-to-top-show-v5-context-menu-icons
http://freestyler.ws/style/20224/fav4-org-black-background
http://freestyler.ws/style/123969/firefox2-tab-colors-plus
http://freestyler.ws/style/124080/firefox2-tab-colors-plus-blue
http://freestyler.ws/style/124024/firefox2-tab-colors-plus-for-halloween
http://freestyler.ws/style/124385/firefox3-small-menubar-mod
http://freestyler.ws/style/124102/firefox3-tab-colors-plus-blue
http://freestyler.ws/style/124320/firefox3-tab-colors-plus-gmail-planets
http://freestyler.ws/style/124432/firefox3-small-menubar-alt
http://freestyler.ws/style/16992/fmo-hot-linked-img-max-size
http://freestyler.ws/style/123606/fx-bookmarklets-icons-for-pgup-pgdn-etc
http://freestyler.ws/style/123320/fx3-hide-menubar-manual
http://freestyler.ws/style/124504/fx3-5-flatstylish-a-flat-style-theme-in-css
http://freestyler.ws/style/124516/fx3-5-flatstylish-tabs-mod-blue
http://freestyler.ws/style/124518/fx3-5-new-tab-button-on-newtab-button
http://freestyler.ws/style/124505/fx3-5-newtab-button-as-whatever
http://freestyler.ws/style/123379/fx3-flatstylish-flatstyle-legacy-version-in-css
http://freestyler.ws/style/124508/fx3-tabs-close-button-dinner-a-show
http://freestyler.ws/style/123599/fx4-vertical-toolbar-background-persona
http://freestyler.ws/style/124802/fx-active-tab-3d-and-shiny
http://freestyler.ws/style/27956/gcal-allday-rainbow
http://freestyler.ws/style/27842/gcal-color-cells-all-one-color
http://freestyler.ws/style/27865/gcal-color-multi-week-cells-linear-gradient
http://freestyler.ws/style/27839/gcal-color-time-band
http://freestyler.ws/style/26973/gcal-color-today-in-multi-week-month-views
http://freestyler.ws/style/28179/gcal-color-year-view-canvas
http://freestyler.ws/style/27935/gcal-colorize-main-grid-starts-on-sun
http://freestyler.ws/style/26103/gcal-colorize-weekends-may2010
http://freestyler.ws/style/27861/gcal-colorize-weekends-starts-on-mon
http://freestyler.ws/style/27860/gcal-colorize-weekends-starts-on-sat
http://freestyler.ws/style/26387/gcal-date-text-centered-multi-week-month
http://freestyler.ws/style/25911/gcal-enlarge-tasks-panel-rhs
http://freestyler.ws/style/42333/gcal-event-color-square-bigger-multi-week
http://freestyler.ws/style/29516/gcal-gadget-header-gradient-color
http://freestyler.ws/style/29542/gcal-gadget-header-gradient-color-hsl
http://freestyler.ws/style/25686/gcal-hi-lite-today-in-multi-week-month-views
http://freestyler.ws/style/25759/gcal-hide-topbar
http://freestyler.ws/style/27952/gcal-hide-topbar-until-hover
http://freestyler.ws/style/26577/gcal-hide-topbar-keep-msgs
http://freestyler.ws/style/27988/gcal-hide-topbar-keep-msgs-and-search
http://freestyler.ws/style/25757/gcal-hide-navbar-left
http://freestyler.ws/style/27937/gcal-hide-navbar-until-hover
http://freestyler.ws/style/42607/gcal-hide-search-box-till-hover-show-google-nav
http://freestyler.ws/style/42240/gcal-hide-search-box-google-nav-till-hover
http://freestyler.ws/style/27847/gcal-horizontal-blue-line
http://freestyler.ws/style/27938/gcal-larger-time-band-font
http://freestyler.ws/style/26010/gcal-more-color-highlighting-other-stuff
http://freestyler.ws/style/26484/gcal-nav-cal-events-hi-lite-i-u
http://freestyler.ws/style/25920/gcal-nav-calendar-day-header-letters
http://freestyler.ws/style/25915/gcal-nav-calendar-hi-lites
http://freestyler.ws/style/41002/gcal-nav-slider-fx4
http://freestyler.ws/style/26107/gcal-no-scrollbar-content-window-may2010
http://freestyler.ws/style/26369/gcal-nonmonth-day-titles-colorized
http://freestyler.ws/style/29621/gcal-print-all-day-week
http://freestyler.ws/style/25983/gcal-set-gadget-header-bg-color
http://freestyler.ws/style/26223/gcal-shorter-gadget-headers
http://freestyler.ws/style/27321/gcal-tasks-panel-background-color
http://freestyler.ws/style/29421/gcal-the-day-begins-6-00am
http://freestyler.ws/style/28065/gcal-wrap-event-title-multi-week-month
http://freestyler.ws/style/11698/gmail-hide-some-hi-lite-some
http://freestyler.ws/style/5749/gmail-all-in-one-hide-and-colorize
http://freestyler.ws/style/30390/gmail-a-little-retrofit
http://freestyler.ws/style/31269/gmail-background-color
http://freestyler.ws/style/31347/gmail-classic-theme-skinned-blue
http://freestyler.ws/style/30226/gmail-color-the-compose-mail-button
http://freestyler.ws/style/31394/gmail-hide-ads-and-move-action-links-lotr
http://freestyler.ws/style/30529/gmail-msg-view-compose-bg-color-font-size
http://freestyler.ws/style/39020/gmail-pick-your-planet
http://freestyler.ws/style/42029/gmail-readability-mods
http://freestyler.ws/style/30034/gmail-select-links-restored
http://freestyler.ws/style/30069/gmail-select-links-restored-for-chrome
http://freestyler.ws/style/42136/gmail-select-links-on-hover
http://freestyler.ws/style/42181/gmail-select-links-on-hover-top-row-only
http://freestyler.ws/style/31259/gmail-select-links-restored-style-settings
http://freestyler.ws/style/5307/google-calendar-colorize-weekends
http://freestyler.ws/style/25632/google-calendar-hide-tasks-in-my-calendars
http://freestyler.ws/style/2464/google-reader-larger-and-serif-plus-wider
http://freestyler.ws/style/12191/google-reader-larger-serif-wider-plus-color
http://freestyler.ws/style/43204/google-reader-more-ninjas
http://freestyler.ws/style/42997/google-reader-ninjas
http://freestyler.ws/style/26198/google-bg-img-nite-lite
http://freestyler.ws/style/26074/google-bg-img-w-see-thru-nav-bar
http://freestyler.ws/style/27997/google-cpdoodlenotifier-unanimated
http://freestyler.ws/style/26496/greader-larger-sans-serif-wider-plus-color
http://freestyler.ws/style/27041/greader-no-text-flow-from-img-lifehacker-com
http://freestyler.ws/style/124415/greasemonkey-favicon-on-statusbar-red-circle
http://freestyler.ws/style/124553/greasemonkey-older-monkey-icon-scroll-red-x
http://freestyler.ws/style/29648/imageshack-img-centered-w-dark-bg
http://freestyler.ws/style/124555/stylish-1-x-mgr-compact-plus
http://freestyler.ws/style/123396/stylish-editor-1-x-tn3270-blue
http://freestyler.ws/style/124390/stylish-editor-amber-text-on-a-black-background
http://freestyler.ws/style/124391/stylish-manager-background-color-striping
http://freestyler.ws/style/124427/stylish-manager-input-box-background-color-font
http://freestyler.ws/style/124422/stylish-manager-low-lite-striping-circles
http://freestyler.ws/style/124438/stylish-mgr-amber-black-w-flatstyle-checkboxes
http://freestyler.ws/style/124530/stylish-mgr-flatstylish-british-blue
http://freestyler.ws/style/124428/stylish-mgr-low-lite-reverse-striping-circles
http://freestyler.ws/style/124387/stylish-sidebar-checkmarks-green-red-cyrkle
http://freestyler.ws/style/124383/stylish-sidebar-remove-labels-from-icons-alt
http://freestyler.ws/style/124379/stylish-sidebar-remove-text-labels-from-icons
http://freestyler.ws/style/29737/us-o-click-screenshot-for-image-tabs
http://freestyler.ws/style/29668/us-o-click-screenshot-for-larger-centered-image
http://freestyler.ws/style/26566/us-o-forum-pagination-more-space
http://freestyler.ws/style/26572/us-o-install-counts-top
http://freestyler.ws/style/26597/us-o-install-counts-float-right
http://freestyler.ws/style/28290/us-o-install-counts-on-hover-tab
http://freestyler.ws/style/27843/us-o-rainbow-header
http://freestyler.ws/style/30458/us-o-whitesmoke-shadow
http://freestyler.ws/style/26237/us-o-wide-screen-shots-custom-s-ized
http://freestyler.ws/style/29817/userscripts-org-nav-fixed-at-top-always-on-top
http://freestyler.ws/style/16043/userscripts-org-readability
http://freestyler.ws/style/11894/userstyles-org-rainbow-ratings-roygbiv
http://freestyler.ws/style/4934/userstyles-org-screenshots-unresized-vertical
http://freestyler.ws/style/11816/userstyles-org-simple-hi-lites-low-lite-kiss
http://freestyler.ws/style/11879/userstyles-org-forum-read-unread-by-color
http://freestyler.ws/style/21819/userstyles-org-delete-the-delete-link
http://freestyler.ws/style/26037/userstyles-org-image-for-the-delete-link
http://freestyler.ws/style/15318/userstyles-org-my-mod-of-british-blue
http://freestyler.ws/style/16251/userstyles-org-new-rating-system-stars
http://freestyler.ws/style/16276/userstyles-org-new-rating-system-ugh-ly-thumbs
http://freestyler.ws/style/12028/userstyles-org-original-rating-stars
http://freestyler.ws/style/12015/userstyles-org-rating-diamonds-blue
http://freestyler.ws/style/12004/userstyles-org-rating-diamonds-green
http://freestyler.ws/style/12011/userstyles-org-rating-diamonds-orange
http://freestyler.ws/style/12014/userstyles-org-rating-diamonds-red
http://freestyler.ws/style/11958/userstyles-org-rating-diamonds-us-o-blue
http://freestyler.ws/style/12018/userstyles-org-rating-diamonds-yellow-2
http://freestyler.ws/style/11997/userstyles-org-rating-diamonds-yellow
http://freestyler.ws/style/12088/userstyles-org-rating-stars-gold-24x24
http://freestyler.ws/style/12072/userstyles-org-rating-stars-gold
http://freestyler.ws/style/15710/userstyles-org-rating-stylish-1-x-icons
http://freestyler.ws/style/11960/userstyles-org-rating-stylish-icons
http://freestyler.ws/style/12203/userstyles-org-screenshots-unresized-plus
http://freestyler.ws/style/15423/userstyles-org-users-menu-green-mini-bar
http://freestyler.ws/style/15420/userstyles-org-users-menu-all-in-a-row