Gigaton Knuckles: I like the idea in theory, but due to how parries work its going to be hard to balance.
Arcane Accuracy: Similar to the old Ammo Scavenger, but due to its cost you cannot really rush it in lane, where it would be the most useful. Also it benefits form high fire rate weapons, it could be changed to use the build up mechanic to allow more heroes to use it.
Light Speed Rounds: I am very much any items that change how guns interact with cover or aiming. I think ricochet and split shot should not be in the game and this item belongs in the same category.
Trigger Fingers: Good assassin item, but would be too good on too many heroes, and the stats are way too good for a T3 item, it should be nerfed or made into a T4. I dont think it should build from opening rounds.
Flash Reload: Either the item is too easy to proc or its op, or its too hard to proc and nobody buys it. Active reload is already one of the best items in the game, and one of the reasons its allowed to be so good is that it doesnt build into anything.
Devouring Resilience: Way too strong, and also heavily biased towards high fire rate guns (Escalating Resilience has the same issue) Basically just a mcg item.
Sacrificial Siphon: I don't like economy items period. It shouldn't build from Monster Rounds, as Monster Rounds is already super strong, no reason to make it stronger.
Psychic Redirection: At worst its a 4.5s self stun. I guess its fine on maybe Ivy and Gray Talon. But it both feels way too expensive and kinda hard to balance.
Ejector Glyph: I think the item is bit weird.
Mystic Rebuke: Way too strong. Builds from an already strong item, and gives silence for only 1600, compared to silence wave which is 3200
Ballistic Rebuke: More balanced than Mystic Rebuke, and might be fine.
Healward: Im pretty sure healing effectiveness as a stat counters anti heal, but I'm not 100% sure, so it could just give more healing effectiveness.
Blink Bangle: Feels op, but might be fine. I assume the recast window resets when you recast it. Also does the active cooldown start when you use the first warp, or after you either lose the buff or cast the last warp.
All other items are good in my opinion.