With help from Noah, we have put together a list of talkgroup ranges for Palmetto 800. The link to the wiki page with the list is here:
Palmetto 800 Talkgroup Ranges - The RadioReference Wiki
In working with these ranges this morning, I note that there is a logical pattern to the talkgroup assignments.
The creator of the list broke the state into three regions - Coastal (1-14999), Mid State (20001-34999) and Upper State (40001-54999). There also ranges for Georgia (55001-59999) and North Carolina (60001-64999).
Within these ranges, there is a pattern - Interoperability talkgroups are first, followed by a block of 500 for each county in the region listed in alphabetical order), followed by a block for state agencies broken into blocks of 100 talkgroups.
Within the three regional blocks for state agencies, there is a logical arrangement to the lists. We're missing, or there may not exist, assigned talkgroups in each of the state agency ranges, but the pattern is clear.
This should make narrowing down active but unidentified talkgroups at least to a specific agency easier.
There are also logical groupings to several of the county blocks of 500. I haven't gotten that granular yet on the list, but anyone is able to edit wiki pages, so feel free to add information as you see fit. It seems clear that each county is left to designate the assignment of groups within their blocks.