Amazing Spider-Man (Vol 1 1963) Issues 251-300

Tom DelFaco (writer) and Ron Frenz (art) team up for most of this Amazing Spider-Man block. 

Key issues include;

#252 - 1st appearance of black alien symbiote costume
#253 - 1st appearance of The Rose
#256 - 1st appearance of the Puma
#257 - 1st appearance of Ned Leeds as the 3rd Hobgoblin, 2nd appearance of the Puma
#265 - 1st appearance of Silver Sable, 1st team appearance of Wild Pack
#280 - 1st appearance of the Sinister Syndicate - Beetle, Rhino, Boomerang, Hydro-man, Speed Demon
#287 - Guest appearance Daredevil
#294 - Death of Kraven The Hunter
#298 - 1st appearance of Carlton Drake & Life Foundation. 1st cover art by Tod McFarlane on Amazing Spider-Man

#299 - 1st cameo appearance of Venom (Raw)CGC Slabbed Version  
#300 - 1st full appearance of Venom, 1st issue inked by Todd McFarlane | CGC Slabbed Version