There are other Oneness organizations.
Here are a couple:
Worldwide Pentecostal Fellowship: generally a bit more conservative than UPC, new org, same basic doctrine
Assemblies of the Lord Jesus Christ: same basic doctrine. The organization is not new, they just never merged with the UPCI. I'd say their holiness standards are about the same as the UPC's. Maybe a bit more liberal than some.
Pentecostal Assemblies of the World: as far as I know, same basic doctrine. The organization isn't new, they don't take quite as strict a stand on "outward holiness".
There are also several loosely organized fellowships (not official organizations) and Independent churches, and a few more orgs I can't think of right now. They vary on "standards" but all teach the same basic
Acts 2:38 doctrine.