Thanks to other topics and threads (thank you George and Mike) I'm just beginning to understand the orders crosses,etc...
If I am not wrong I see on these engravings ( end XVIIIth century):
The collar of Saint Andrew and on the right Saint Alexandre of the Neva.
Engraving number 7: Saint Andrew (blue) reserved to the Imperial family, other sovereigns and very high ranked persons from the aristocracy . Founded in 1698 by Peter the Great.The most distinguished order on the hierarchy.
Engraving 42 : Saint Alexandre of the Neva (red) reserved to highly ranked civil or military nobility. Founded by Catherine the first 1725.
Engraving 43 : Saint Catherine (red with golden dotten line on the border)reserved to women: Imperial Family and very high ranked ladies of the aritocracy. Founded by Peter the Great 1714.
Last one is Saint Andrew the Apostle
Hope it is the right answer...