AMSAT-DL proposed a bandplan for the NB-transponder. Perhaps it would be an idea to enrich this bandplan with 'center of activities' or calling frequencies, like many IARU VHF/UHF/SHF bandplans have (look e.g. here). One of the advantages is that one specific frequency can be monitored for DX and/or rare activities and, that the other side / rare activity knows where to call (and QSY to another frequency).
Of course nowadays the whole spectrum can be viewed with SDR's etc. However, knowing where and what to monitor specifically may be comfortable and prevents numerous mouse clicks on the waterfall/spectrum to discover that the peak you see is a station you already worked 20 times ; -)
Constructive opinions are very appreciated and, as a proposal (everything is fine with me, as long it's harmonized) I suggest: