There is a pretty Amber inspired part in the Lion & Dragon Companion where the use of Tarot is discussed! The Pathwalking high level ability is pretty neat. While the divination use of tarot is expected, the invocation rules are less so, and they are a nice straight forward lead in toward the more powerful Pathwalking. It is a magic addition to Lion & Dragon that isn't weighted down with excess, as often happens with supplement magic schools/systems. It is also an excuse to buy a neat set of Medieval styled tarot. nice
To be honest, that's not inspired by Amber at all. Using tarot cards for pathworking has been part of the magical tradition for a very long time. It may not actually date all the way back to the medieval period, but it has been around since way before Roger Zelazny was even born.
I don't know if Zelazny knew this when he invented the use of Trump Cards in Amber, or if it was just coincidence.
But I'm glad you liked the mechanics in the Old School Companion. In any case, all the various additional magical techniques and grimoires in the Old School Companion are based directly from historical sources.