Is There an Approved List of Third Party Apps?

Lokea

I've seen only this UOPro - UOGuide, the Ultima Online Encyclopedia:

There were 7 applications accepted into the program.

• UOAssist - The must have program to play the Classic Client with
• UO Auto-Map - A mapping application for UO
• Ultima Mapper - A modern mapping application for UO Classic and Enhanced clients. (Reference)
• UO Curse Tool - Spout profanity the Old English way
• UO Journal Converter - A useful tool for handling saved Journal files
• UO Magic Tool - A tool to keep track of Reagents and cast spells
• UO Spawn Map - Helps you locate specific monsters and spawning areas

Some of those haven't been updated in 20+ years.

And the last one added, Ultima Mapper, was added over a decade ago:

New 3rd Party Program Approved For UO: UO Mapper – Ultima Online

Mainly, I'm after a better mapper, and while Ultima Mapper looks great, I had some issues getting it to run, and I know there are several other mapping programs out there. Before spending the time debugging my Ultima Mapper install, I'd like to know if UO Cartographer and Mapistro are approved, because I've seen then recommended here on the UO.com forums. I will probably go with Mapper, but I'd like to know what the (legal) options are.

Grimbeard

The enhanced client has a great mapping system 

Lokea

Grimbeard said:

The enhanced client has a great mapping system 

It is, but I've seen features on some of the third party mappers that I would love to have - better zoom, etc. If I have to keep using the EC's built-in system, that's fine, but if there's something better and approved, I'd rather use it.

Lord_Frodo

UORudder and UOHomeowner are still OK

Community Manager

Officially speaking, as far as 3rd party programs go ClassicUO Web Client and Pinco's are the approved 3rd party clients for CC and EC. 

If you are talking about programs to enhance specific aspects of the game, I do know that UOA is still approved as well as UOCartographer.

I do not have a full list, but I can see if I can get one to give to Mariah for uo.com.