Where to even begin?
-A Birds of Prey series/Gail Simone tribute show. Start with Oracle recruiting Black Canary, gradually flesh out the team with Huntress forcing herself onto the team after working with Black Canary and realizing that there’s more going on there, Lady Blackhawk after needing her help for a mission and, finally, Giganta as the team’s muscle. Note that this Giganta would be based on the one from Gail Simone’s All New Atom run, semi-reformed, and with Ryan Choi as a supporting character as Giganta’s super-supportive boyfriend.
-Teen Titans Season 6. There’s been a time lapse, so all the characters are older. Jericho’s on the team, Robin’s Nightwing, Beast Boy goes by Changeling, Raven wears white, and they all have updated character designs. In the season finale, the Justice League falls under outside control, and Batman’s contingency for this (aka the Titans) is activated, and they’re brought to the Watchtower to fight the mind controlled League. At the end, they decide to accept League membership, with the final few seconds introducing a new line-up for Season 7. My choices would be Robin (Tim Drake), Steel (Natasha Irons), Traci 13, Blue Beetle (Jaime Reyes), and Bombshell, with Ravager (Rose Wilson) joining later as a sort of “sixth ranger” character. There would also be a new Titans East.
-Legion of Superheroes Season 3, or at least an original movie. Something to tie up the loose ends and bring the show to a satisfactory conclusion.
-Justice League International, an action-comedy series essentially about a B-list superteam, constantly in the shadow of the big names.
-A series of DC Universe exclusive original shorts, akin to the DC Showcases they did years back, and are apparently planning to do again to accompany the animated movies.
-A future series in which Batman takes his training young heroes thing to the logical extreme and opens a school that secretly takes in young metahumans and budding superheroes and provides a place for them to train and grow. A show about a small school for metahumans (not necessarily superheroes) and a small number of non-powered would-be superheroes, featuring some established characters, like Jon Kent, Mar’i Grayson, and Jai and Iris West, along with some original characters.
Honestly, I could keep going forever.