What fallows is a list of SMP mods. I realize this has already been done by poeman but his list is so hopelessly out dated I decided I would pick up where he left off. (Please forgive any misspellings, spelling is not a strong point for me, but i will try.)
I have tried to avoid linking mods which are ether very outdated and/or do not seem likely to be updated any time soon.
Content mods (Mods that add new things, not ones that utilize what's already there):