0;Gossip
1;Quest Giver
2;UNK1
3;UNK2
4;Trainer
5;Class Trainer 
6;Profession Trainer
7;Vendor
8;Vendor Ammo
9;Vendor Food
10;Vendor Poison
11;Vendor Reagent
12;Repairer
13;Flight Master
14;Spirit Healer
15;Spirit Guide
16;Innkeeper
17;Banker
18;Petitioner
19;Tabard Designer
20;Battlemaster
21;Auctioneer
22;Stable Master
23;Guild Banker
24;Spellclick
25;PLAYER_VEHICLE (players with mounts that have vehicle data should have it set)
26;Mailbox (GUARD?)
27;UNK4 (OUTDOORPVP?)