DL domestic fares often permit connections in focus cities in addition to hubs (such as RDU/CVG/BNA/AUS) and some of them allow LAS connections (see below). But, yeah, that's pretty much it.
PUBLISHED RTG SEA-SJC/DL9089/TAR-DRG1 EF-29MAR20 DIS-INDEF
MAP CONSTRUCTED LEFT TO RIGHT AND RIGHT TO LEFT
1. SEA-LAS/LAX/SEA/SLC-SJC
2. SEA-LAX-SJC
3. SEA-SLC-LAX-SJC
4. SEA-SLC-SJC