So many amazing ones posted, I'll just add
. I think Goku saving his friends during the Saiyan Saga is up there for me, same for Super Saiyan debut, Super Saiyan 2 debut, and so many other truly iconic moments.
My favourite characters were Gohan, Vegeta, Goku and Yamcha (I know he's a huge meme, but I really appreciated him during OG Dragon Ball when he went from capable yet goofy bandit to trusty friend, plus Wolf-And Fist has always been a cool move to me).
If I had to choose an absolute favourite character that would probably be Gohan. Seeing him go from timid kid that had a ton of potential to pacifist that ended up fully exploring said potential was great. I also loved Saiyaman as goofy as he was, was nice to see Gohan just enjoying himself without any huge threats around even if that didn't last too long. I'm glad we got Gohan Blanco/Beast Gohan in the last film, sure it was rehashing old moments and ideas, but it was nice to know Toriyama still wanted to bring back Gohan into the forefront of things. Same for Piccolo, who's always been amazing.
Dragon Ball's just such an amazing franchise with plenty of great moments. It's what got me into anime, and I remember when I first heard there was an OG series, kid me did his best to watch as much of it as he could. Goku was so innocent and lovable then, and it was really satisfying going through the whole series and seeing his progression as a person whilst staying that endearing fighter.
Vegeta was my absolute favourite as a kid. I was rooting for him to win all the way, and he's still the best character to me even now though I still hold Goku and Gohan in high regard even in that discussion (though obviously their purposes are quite different). Vegeta's transition from villain to hero was honestly astounding, especially since it wasn't a drastic shift, he was spared and throughout Namek we still see him as an intimidating character that's drastically different from Goku, but despite that put his hopes in Goku to best Freiza, then we see him constantly push himself to try and surpass Goku. To see him later question himself as a fighter at the end of the Cell Saga and to see him acknowledge Goku as better during the Buu Saga were very fulfilling as a fan. He really grew and was one of the best parts of the series.
I don't rate Super super high, but it serves as a nice love letter to Dragon Ball in a lot of ways when it simply takes what was already established and tries to give respect from there. Ultra Instinct for instance is such a cool power-up, and showed that Dragon Ball still had some iconic ideas left. I also really liked Zamasu. Speaking of villains, Dragon Ball just had so many memorable ones, from Frieza to Cell, even Buu was really intimidating to kid me due to his chaotic nature.
I just really love this series, and I'm definitely gonna have to rewatch it all from scratch, read it too. Toriyama really left an impact and I hope he's resting peacefully.