Well here's a fun thing to do right here in the forum.
How would you have continued the story after Z? Instead of Super, it's your show. How many saga's would there be? who are the villains? what are the Z fighters doing?
How much time passes?
I'll start.
I'd start the series a few years after Buu's defeat, with Trunks and Gotten about 12 years in age, a little taller. They'd be about Gohan's size during the Cell saga.
1. Tournament saga.
First arch is a tournament with pretty much just the Z fighters competing. People are no longer oblivious to their power, they have seen it enough times during the last tournament. The only non- Z fighters that compete would have limited ki abilities at least.
The Z fighters have agreed on two rules for this tournament: No transformations, and they keep their power level limited so that all of them are at the exact same power level. Master Roshi or Korin can be there as the judge since they are good with power levels.
It would again be a tournament about techniques and tactics, and not about power levels. And it would not be interrupted by villains.
The non Z fighters would be first to be beaten, but some could put up a good fight. Crane Hermit could return with new students, one of which could actually reach the power limit that the Z fighters put up between themselves while the others would be too weak. This guy is beaten by Tien, and takes his loss very seriously. Being former Crane, his very goal would be to defeat the former top student. He would take his loss hard but we get back to that later.
In this tournament, the least experienced fighters are defeated first.
Goten, Trunks, Gohan and Ciao-Tsu are first out due to lack of experience. Yamcha just after them.
Some interesting match ups would take place:
Tien vs Vegeta.
Vegetal would obviously be overconfident here and Tien would surprise him with many techniques, dominating a lot of the match. Vegeta does narrowly win in the end though by playing a bit dirty and doing something tactical. Both now have some mutual respect for each other, they are both warriors after all and of a more similar mindset about training.
Krillin vs Goku.
It would be a great callback to the past, and they would fight pretty even but eventually Krillin gets the upper hand and wins since he has more talent with new techniques and tactics while for Goku the main technique has always been to pull transformations and extra power out of his butt. Which he can't do now.
Piccolo vs Majin Buu.
Both regenerating and using various abilities, Piccolo would win in the end since he simply is a better fighter. Buu could possibly be disqualified by raising his power too high.
The finale would be Vegeta against Piccolo.
Would be a very long and brutal finale, one in which both of them push themselves to the limits, getting increasingly more brutal since well, they know the other can take it and would do the same. In the end, Piccolo wins with an energy shot from the mouth when Vegeta has him grappled and ready to push out of the arena.
2. Demon saga.
The crane student mentioned earlier, seeks power in dark places. He draws it from the demon realm, returning more powerful and challenges Tien.
Their fight draws the attention of other Z fighters who arrive soon, Goku is ready to jump in but Vegeta stops him. As a warrior and now respecting Tien more, he sees this is Tien's fight and they should not interfere.
Tien would use his full power here, gets nearly beaten to death by this crane student but manages to win with a new technique: He uses the four witches technique to get more arms and uses two to power up a tri-beam as he forces his opponent to move to the right position with Dodon rays from his remaining hands. The crane student is battered and defeated, and the demon power now claims him, taking full control and transforming his body to a stronger form.
Krillin and Yamcha now jump in to help, Goku could encourage them to fight thinking its more on their level and that he is not needed here while Vegeta could simply claim no warrior from earth could be a challenge for him.
The demon could however kill Tien, and when Piccolo arrives to fight him, it could abandon the old body to instead merge with Piccolo, him being kind of a demon could make this easier.
So now they face a Piccolo who is far stronger than before, and as vicious as his father was. Krillin and Yamcha withdraw, heavily wounded and clearly outmatched. Goku and Vegeta fight him in turns, until Piccolo takes advantage of Goku's soft side and kills him.
Afterwards Vegeta holds nothing back and actually is still stronger but Piccolo regenerates faster now causing him to beat him in the end.
Gohan and Buu arrive then, and Gohan still has it difficult to fight his mentor and friend despite him having killed Goku already.
When Piccolo also kills Buu however after a tough fight, Gohan is pushed further, and unleashes a fury like he used to as a kid when pushed too far, overpowering Piccolo and destroys him until almost nothing remains and he is thought dead. The demon leaves his body, and just when it is about to claim Vegeta as a new host, master Roshi shows up and gives a small but serious speech as he performs the evil containment wave which claims his life but captures the demon.
The demon's prison is kept safe by Dende until they find a way to destroy it permanently.
Goku is brought back to life with the dragon balls, Roshi chooses to stay dead (he found some pretty girls in the after life) and Tien does not want to be wished back yet, he stays dead to train. First with Olibu, and later with others to return later.
Now the story moves forward, showing some scenes surrounding the final episode of Dragonball Z and after it.
3. Shadow of the Saiyans saga.
A new dominant power has risen in the galaxy. Goku was not the only Saiyan send to another planet as a kid to destroy it as an adult, other Saiyans who survived the destruction of their planet found each other, banded together, learned of Frieza being behind it and laid low. Once Frieza and his father where destroyed, they obliterated what remained of Frieza's forces and grew stronger through this war and they now run the same scheme of conquering planets and selling them to the highest bidder.
So now something familiar happens: Two saiyan pods land on earth.
Vegeta finds them first and talks with them, they don't recognize him as their prince and call him soft. As Vegeta is about to power up and boast about his power, Yamcha arrives along with Goten and Trunks. Them being teenagers now, they get along quite fine with Yamcha who is rather laid back and has similar interests, he's like the cool uncle to hang out with which they did until they felt this power and investigated.
Yamcha gets confident and wants to get even for last time Saiyans arrive on earth, and Vegeta humors him.
Yamcha fights one of the Saiyans one on one, and defeats him with a kamehameha, leaving him heavily wounded.
The second Saiyan then steps in and defeats him easily. Vegeta now tells Trunks that this would be good exercise for him, Trunks fights the Saiyan while Vegeta points out his every mistake.
Surprisingly, the Saiyan goes super saiyan and proves to be stronger than Trunks, Goten then jumps in and gets to fight him alone for a while when Trunks is knocked out. When things look bad, Vegeta finishes off this Saiyan effortlessly while saving the teens and berating them for their mistakes.
The weaker Saiyan escapes however, heavily wounded.
4. Saiyan empire saga.
The weaker saiyan warns the others and they plan to return with greater numbers. Foreseeing this however and with the help of King Kai, a number of the Z fighters go into space to take the fight to them, away from earth.
Goku, Vegeta, Piccolo, Gohan, Trunks, Goten and Uub all leave earth for this and fight against the Saiyans on alien planets and space ships.
In the meanwhile the demon breaks free back on earth and now takes physical form without a body, having forged its own over the years and used it to break out. Krillin, Yamcha, 18 and 17 are now forced to fight this battle on their own. It's a tough battle, they have good moments but can't win and 17 dies. When all seems hopeless, the dragon balls have been gathered and by his request, Tien is brought back to life and kills the demon with an improved version of the evil containment wave, one that destroys demons without claiming his life.
Tien is now much stronger as well due to years of training in otherworld. Goku has sensed the threat and teleports back to earth only to find out Tien already saved it, he takes Tien with him back to the fight, Tien now being of about the same power as Piccolo.
Getting separated during the fights against all these Saiyans, everyone gets involved in some intense battles. Goku and Vegeta attack the leader while the others take on the rest.
Goten and Trunks really come into their own here, developing more of their own techniques and fighting more separately. They try to fusion but their opponent manages to end it with a technique.
Tien and Piccolo manage to push themselves to new heights as well, coming up with new techniques as they fight and increasing their power.
The weak Saiyan who was the first they encountered is encountered several more times, getting beaten up again to near death several times but managing to escape, always hiding his increased power until it is too late and he is stronger than any other Saiyan due to the zenkai boosts.
Goku and Vegeta manage to kill him together with a combined attack, which however claims their lives.
With the Saiyans defeated, a lot of them dead, the remaining ones surrender and are kept under close watch. Their planet dealing days are over.
Trunks and Goten meet a Saiyan twin in the aftermath however amongst these survivors and they start dating them. (with some hilarious moments early on when they can't tell them apart which Saiyan women might respond more fiercely to than a regular woman.)
Goku and Vegeta do not return, the torch has finally truly been passed on for the final saga a few years later.
Goten and Trunks are now young adults, Pan is about 8 years old. Krillin, Yamcha and Tien have started a martial arts school together, a new one. Neither crane or turtle. They train a new generation of human warriors, with their recent victory against the demon they feel that humanity should be capable of defending their own planet.
Marron is one of the students. Both her parents fight after all.
Gohan is not a fighter, and is quite happy with his family life. Mainly he just trains with Pan now for fun, not too seriously.
5. The lord of death.
For the final chapter, a powerful Namekian sorcerer arrives on earth, gathers the dragon balls and increases their power before he makes a wish.
His wish is to revive the most powerful beings who threatened earth, and with the second wish he makes them obedient. In death many of them have become stronger.
The returned warriors are: King Piccolo, Raditz, Nappa, Frieza, King Cold, Dr Gero, Cell, Dabura, Babidi and the stronger Saiyan who Vegeta blew up.
They are all send after another Z fighter:
-King Piccolo fights Piccolo.
-Raditz and Nappa crash the new martial arts school to fight Krillin, Tien and Yamcha.
-Cell fights against Gohan.
-Frieza fights against Trunks.
-Dabura fights against Uub.
-the stronger Saiyan fights against Goten.
-Dr Gero fights against 18.
In the meanwhile Babidi is not under control since thats kind of his thing, the wish did not work. As he clashes with the sorcerer, King Cold is accidentally freed from the control as well when the Namekian kills Babidi. Now King Cold takes charge and commands the sorcerer. Instead of aiding anyone of the combatants, he lets them all die. When Frieza is about to die, he even betrays him and finishes him off himself.
Through the sorcery of the Namekian, King Cold absorbs their power and fights the Z fighters, overpowering most of them as he transforms several times through the battle until Goten and Trunks are the only ones left standing who can take him on.
King Cold takes on a new form even, beyond anything Frieza did. Not a tacky gold, but a shiny white silver form with ice blue eyes.
They defeat him together when Goten does a spirit bomb, his father telling him from beyond the grave to have faith and do it.
And Trunks creates a new attack that combines something of his own and of Vegeta, being spoken to as well by his father beyond the grave.
Trunks attack is the surprise attack to hit Cold in the back, destroying him between their attacks.
And so ends the series, with Goten and Trunks solidified as the new protectors, possibly fathering their first kids. Who could bear a resemblance to Goku and Vegeta. And the three human Z fighters training increasingly stronger students who could have an average power level of around 10000 at that point. Pan and Uub could be fighting too of course, and Gohan being quite happy that he does not have to.
Piccolo could return to Namek, and the series could end with Pan deciding to hunt for the dragon balls.