Good Reference For Searching Circulated Currency?

I am mainly a coin collector, but I do have a growing currency collection. It consists mainly of some silver certificates, $2 bills, RADAR note, repeater note and mostly star notes. Probably under 100 notes in total.

I would like to start searching $1 "straps" from local banks looking for finds like I did with searching rolls of cents and finding the occasional Wheat cent or Indian Head cent.

Is there an online reference of the more scarce/rare things to look for? I already know about the usual suspects (silver certificates, star notes, RADAR, repeater and ladder notes, binaries and trinaries, Barr notes and obvious errors). I am referring to any not as well known such as signature combinations, low mintage and anything else to look for.

Thanks in advance for the reply.

Dave G.