Well, have a few magical ideas for people to vote on.
Ghost Bullets
Bullets have an unfortunate tendency to hit solid objects and not penetrate them. Ghosts have the ability to bypass solid objects and kill the living things behind them. Therefor, what we need to invent are Ghost Bullets, which can penetrate annoying cover and body armor and then kill the enemy behind them. Perhaps bullets can be converted into ghosts through ceremonially killing them? Or maybe we'll need to invent some new ghost ores to forge them from, or perhaps some sort of spell can be invented that can invert things into the underworld for a short while.
Video Game Pockets
So, in video games, the main character can always carry along a whole armies worth of stuff in their back pocket. Let's replicate that. While there were some suggestions of things like attached pocket dimensions or such, the easiest way is probably to enchant the pocket to be bigger on the inside then the outside. Being bigger on the inside is seen in a lot of fantasy settings, so it's worth checking out, and who doesn't want to be able to fit a full rocket launcher into their back pocket? When this project is done, it should help a lot in smuggling, both of shiny profitable things and of weapons past enemy guards, as well as allowing our agents to carry far more gear.
Holographic Computer
For ages now, they've been telling us that the next step in computer systems will be optical computers, which use light to do computer stuff. There's a form of magic that uses light to make false images and so on. It seems to me that there's a point where those two concepts meet. After all, what does it matter if the signals are fake as long as they lasts long enough to talk to other computers and pass on the optical speed calculations to them? So let's make an illusionary computer that is both made out of light and runs on light instead of electricity. The Optical Revolution will be ours!
Was reminded we have have 1980-1990 level tech right now instead of 20?? level tech.