https://www.nexus.org.uk/bus/timetables?tid=All&title=&page=4 - all the 9xx services are all work services in the North East.

I'm not sure how tight the rules are but there's also the:

22X / X39 - Newcastle to Cobalt (SNE / GNE)
90 - Winlaton to Team Valley (Nexus / GCT)
91 - Newcastle to Team Valley (GNE)
92 - Heworth to Team Valley (Nexus / A Line)
19 - Ashington to North Shields via Cobalt (daily extension) (GNE / Nexus)
52 - Ashington to Newcastle via HMRC / Quorum (daily extension) (ANE)
101 - Middlesbrough to Teesport Tesco distribution depot. (SNE)
552 - Great Park - DWP Tyneview Park (Nexus / Phoenix)
555 - Four Lane Ends to Quorum (ANE)
575 - Horsley Hill - Bede Ind. Estate (Nexus / SNE)
592 - Roker - Doxford Park (Nexus / GCT)
593 - Pallion - Doxford Park (Nexus / GCT)
792 - Blackhall Mill - DWP Tyneview Park (Nexus / A-line)
794 - Stanley - HMRC Benton Park View (Nexus / Weardale)

I also believe the 2A in Darlington (ANE) is subsidised to serve Amazon aswell.