Extremely casual [Oberon Prime] build, designed around using as little forma as possible and built for Defense and Interception missions in particular. Use your 2 and check Twitter on your phone while the waves progress themselves.
[Steel Charge] is not ideal, but it's used because you get more points to work with and that means less forma. I would personally prefer Energy Siphon, but Growing Power and Corrosive Projection both work fine.
[Augur Reach] is definitely not necessary, but using both [Transient Fortitude] and Blind Rage would require at least three forma (or two forma and a Power Drift that's one point away from fully leveled)
Neither Arcane is necessary. I take these two because I like them. Everyone but Hildryn and Lavos loves Arcane Energize.
If you do go the TF+BR route you get a ton of power strength but a lot less flexibility with your tanked efficiency. Doing so makes Zenurik focus and Arcane Energize pretty much mandatory. Otherwise they're both optional.
This build can transition into an actual endgame build since you'll want that D polarity for Adaptation or Rolling Guard anyway. As-is it's really just for standard, low intensity star chart farming.