Any Jacksonville FL Recommendations?

Going to be in Jacksonville for the first time in years this Friday and Saturday - JUST Jacksonville; won't have time for any side-trips unfortunately due to work meetings mixed with a little time off.

Already planning on a trip to Mayor's and Underwood's, possibly a joint called A-1 Coin & Stamp that seems to have or have had a decent vintage selection over the years - does anyone have any recommendations for other spots to check out? I'll mostly be in the downtown area but would love to pop in to as many spots as I can as I'm usually further north up the coast when I travel these days (Carolinas, etc)

Thanks for any tips or thoughts!