Identify older breaker type. Pictures
One of the types of breakers mentioned in the panel label, Bryant GFCB, are still made.  Bryant was bought by Eaton some time back, so they are now known as Eaton BR   GFCI series.  Most big box and stores stock them, or any electrical supply house will be able to get them for you.  



Image from Home Depot - Eaton Type BR GFCB

Interestingly, as Harper notes in the comments, regular non-GFCI type BR breakers are not listed for use with this panel for some reason.  I expect they would still be safe to use since the busing is identical on regular and GCFI type BR breakers, but it would not pass an inspection that way since it is not listed for that use.  So the only currently manufactured breakers originally listed for use with this panel are going to be GFCI type.  

It appears that Eaton also makes some cross-listed breakers that are compatible with the original Crouse-Hinds ones.  See this PDF for more details