Not everyone has access for uploading of files to Subsim, many modders put their stuff on their own pages at Filefront or other file-sharing sites.
There is a great archive of mods here, though - pretty much everything I've ever looked for has been there:
ftp://hartmuthaas.no-ip.org/Volume_1...3COMMUNITYMODS
You will probably need to log in, if so:
username: Maik
password: Woelfe
The only small downside is that mods are arranged by name or nickname of the modder, but if you don't know who did a specific one you can always ask. If it's a mod currently in use someone will surely know, if not then they can probably point you to something else that superceded it.