My build was based entirely around bombers, rockets, and the psychics. Bombers and GEET to generate rockets which (multiplied by poison, ice, and Excalibur) were the main damage component of the build, reached about 1.5G damage at the end.
Bombers synchronize really well with the psychics since you get the same benefit from Timeshift by investing 2 extra points into psychics as you would from investing those points into Timeshift itself, but you also get the extra psychics on top of that.
These guys will take care of all your collection needs, though if I were going for a pure speed strat (and not trying to unlock extra perk points, as I was on this run), I’m not sure I would bother with them.
Use the perk that lets your gunners fire arrows and put fire arrows on them to keep the rock on fire permanently for massive boost to the Bombers speed, which will generate even more Timeshifts and rockets.
Also take the perk that causes them to fire grenades on reload, it won’t be a ton but it will help generate some weak points that you can trigger with your rockets for faster Excalibur triggers.
Finally ran 10 mountaineers purely for the Inspiration bonus on your collectors (doubles their carrying capacity – again, not useful if you aren’t going for perk point unlocks).
Didn’t even touch slammers or drones.
Note: Completed speedrun with basically the same strategy at 29:20. Went all in on Timeshift and didn’t bother with psychics, but I’m not sure it was actually helpful. I was definitely blocked by lack of shards more than anything else throughout the run, mostly in late game housing and rocket upgrade costs.
You essentially lose 1 perk point on Timeshift by going for the psychics but I think it’s probably worth it, since the late game damage scaling is all about pumping out more bombers and rocket upgrades, which gets expensive.