Having just completed Steins;Gate — Rebellion of the Missing Ring (Boukan no Rebellion) a random thought that comes to my mind is the possibility of another spin off manga following Suzuha.
Spoilers for Steins;Gate below
As the happy ending for Suzuha has her living her life in 1975,a slice of life spin-off following her random adventures and thoughts through the past she lived in could make for an interesting read, especially as she progressively grows older and matures.
Boukan no Rebellion had some cutesy moments, and I think these moments could translate well over into a slice of life manga. It could be even cuter if she met Daru when he was a little boy.