when you make any charactor they come with starting gear but what do dice and cards do? Also for psykers what does the book of imperial saints do?

Dice & Cards: useful for gambling, passing time on guard duty and distracting people. Not to mention being able to be used as a focus for psykers.

Book of saints: Useful for making the character feel like a very small cog in a very big machine.

They offer no bonuses, just act as fluff stuff for the characters, thingsd they will have picked up along the road of life kind of thing. This is 40k dont forget, no picts of lovedones in the wallet, just constant war...

I'd count a book of saints as a charm. Dice and cards are necessary tools for gambling, and can also be useful for some applications of Inquiry and Charm.

The book of Imperial Saints can also be used as a handy reference sheet should any NPC mention a saint, a handy proof on non-heretical status when faced with angry mobs and if truely necessary props up the Scintilla 403-pattern single duvan bed by the requisite 3.4 centimetres required for a level and peaceful night's sleep.

The cards and dice are used for gambling, studies on probability and potentially role-playing games, although those last ones tend to be banned in the grim, dark future as the tools of chaos.