to be honest i used the random tables to put every cypher in my games. Otherwise i would get overly worried about whether or not each one would be useful. Randoming them all was my way of saying "screw it, the pcs can work it out". The option to sell the ones that don't want is also there, i think the default value was like 25... tokens of currency.... (i forget the setting term) which is a decent ammount.

The Technology Compendium - Sir Arthur’s Guide to the Numenera splat adds a ton of extra cyphers and some good tables that references the core books cyphers as well.

Also stashing them around the place is viable.

As a side note; if you're looking at the books, i don't want to say Character Options splat is necessary... but i would highly recommend it if you decide to run a game.