TrekMD

Clearly these people never had teenage boys in the house. 

These are rather....unique thrones....

OK, I consider myself an expert on the Atari 8-bit computers because I had one since 82 and love it still.  There are TONS of great games, so it would be hard to give a limited list.  

Given that you know the 7800 so well, you should consider starting with the 7800 conversions.  One on One basketball (more stark graphics, but faster gameplay), Karateka (absolutely a classic on 8-bit, but you'll need a keyboard), Ballblazer (faster than 7800 on OLDER technology), Donkey Kong (faster, better sound), etc.  I think that will give you a great perspective on how well designed the 8-bits were.  
Beyond that and also beyond the great included games, you MUST check out Blue Max, Preppie 1 and 2, Archon, and many more.  
 

I don't normally post "Reaction Videos", but I really want you guys too see the talent this kid has.  Mind you this kid is only 14 years old, but plays better than most adults.  In fact she's sat in with many professional bands and on some school nights actually frequents Whisky A Go Go where she gets up on the stage with musicians she's never met to play live music.
 

Nice piano arrangement of Sweet Child O' Mine...
 

Atari 7800 Forever mourns the loss of Donkey Kong 😞 #atari #Mariokart #nintendoswitch #donkeykong 
 
 

Yep, I'm a really bad influence!  😆

Yep. I blame you. Its also purchased my first (4-port) 5200 after we talked about that console at the Classic Game Fest in Austin (2014 IIRC). We were looking at the 5200s that Al had set up. One was running Tempest, which caught my eye. Its all your fault.😉