I put all my core and 6 expansions in order in my set and I find I have 30 tactic and Unit cards that don't have a territory race icon. And I expect those are Scriven do the Scriven not have a terrirtory race symbol?

I think you're referring to the SKAVEN.

SKAVEN is a neutral destruction-only race, they don't have a Capital board.
In order to build a SKAVEN deck you need to choose a destruction faction capital board (ORC, CHAOS or DARK ELF) and mix the SKAVEN cards with cards from the chosen faction. Since the SKAVEN units have a good synergy with some DARK ELF cards, DARK ELF-SKAVEN used to be a popular build when the SKAVEN were released. They were also very powerful when mixed with ORCS, SKAVEN units are cheap and really improved the rush centric ORC decks.

Since the neutral cards don’t have loyalty symbols they can be easily used by any faction. However, some neutral cards have a restriction (order only or destruction only). SKAVEN cards are always destruction only cards.