The Great Unified Tcl/Tk Extension Repository is an index of Tcl extensions, maintained by Joe English.
As of 2013-12, it is still being actively updated.
18 Dec 2013 The gutter is moving to a new location: <URL: http://core.tcl-lang.org/jenglish/gutter/ >. Please update your bookmarks.
LV Too bad there isn't an interface for submitting new entries, or updates to existing entries.
JE Sure there is -- post to comp.lang.tcl or email the administrator :-) Data collection is based on "pull" mode -- gathering links from existing sources like SoureForge, Freshmeat and Usenet (primarily Usenet nowadays). So far that's worked out pretty well, and seems preferable to asking package authors to do One More Thing when they make a release.
LV I don't see anything here or on the web page to indicate who the administrator is, let alone how to email them.
Lars H: A example of what web-based uploads could look like is provided by CTAN (The Comprehensive TeX Archive Network):
Suggestions from SYStems concerning a command-line client moved to Tcl Repository Wish List
RS isn't sure whether the name helps in advertising Tcl: "Oh, you need tdom - just get it from the gutter"
LV Would CANTCL be better advertising?
st3ve Yes, virtually anything would be better than "gutter". Now watch, someone'll come up with an acronym for S.H.I.T.H.O.L.E. and that'll be the next big extension repository..;)
NEM would like to applaud Joe for spending the effort in getting this set up. Hope it succeeds. It's already looking like a useful resource.
LV Yes, I too want to say thank you for working hard on this.
pmarin What is "tcl repository notes" in the See also section? I only can see a login page.
jenglish That was a link to a third-party whitepaper, now dead; link has been removed.
The author should put the email for adding new packages. I think is a huge effort for only one person.
jenglish That has turned out not to be the case. I typically only spend about 10-15 minutes a week keeping it up to date (that's on top of following comp.lang.tcl and the tcl-core mailing list, which I do anyway.) An automated submission form or email link would require dealing with SPAM, which in my experience sucks up quite a bit more time. So this probably won't be automated in the foreseeable future.