[PF1e(/USoP)] Concentration bonuses?

[ezekielraiden]

Looking for bonuses to concentration, other than from spells, that are valid in first-party Pathfinder and Ultimate Spheres of Power. Vast preference for truly generic bonuses, not just Casting Defensively, but both types are useful if they stack. Stuff coming from class levels or traits is likely not super useful to me, since my choices are made on those fronts, but if there's a notable juicy one, feel free to mention it just in case it helps someone else. Again, no spells, this is for a no-Vancian-spellcasting game.

I am of course aware that increasing my casting ability modifier is useful, but am leaving that out of this--those are sort of freebies.

What I've found thus far:

Generic Checks
Uncanny Concentration (https://www.d20pfsrd.com/feats/general-feats/uncanny-concentration/) (+2 untyped, feat, req. Combat Casting)
Tunic of Careful Casting (https://www.d20pfsrd.com/magic-items/wondrous-items/r-z/tunic-of-careful-casting/) (+2 untyped, item)
Focus Chew (https://aonprd.com/EquipmentMiscDisplay.aspx?ItemName=Focus%20chew) (+2 alchemical, 1 hr consumable)
Mage's assistant tincture (https://aonprd.com/EquipmentMiscDisplay.aspx?ItemName=Mage%27s%20assi stant) (+5 alchemical, 1 hr consumable, negative secondary effects)

Only Casting Defensively
Combat Casting (https://www.d20pfsrd.com/feats/general-feats/combat-casting) (+4 untyped, feat)
Gloves of Elvenkind (https://www.d20pfsrd.com/magic-items/wondrous-items/e-g/gloves-of-elvenkind/) (+5 competence, item)
Spellguard Bracers (https://www.d20pfsrd.com/magic-items/wondrous-items/a-b/spellguard-bracers/) (+2 untyped, item, also 3/day reroll of casting defensively checks taking better result)

Indirect benefits (e.g. CL bonuses)
Orange prism ioun stone (+1 untyped CL bonus, item, very expensive)
Numerology Cylinder (https://www.d20pfsrd.com/magic-items/wondrous-items/m-p/numerology-cylinder/) (+2 insight for CL checks, item, req. daily skill check)

For various reasons, it's basically always worth my time to pick up reliable bonuses to (generic) concentration checks, so if you have something, feel free to chime in.

[Calthropstu]

If you cast from charisma, the circlet of persuasion applies as concentration is a charisma based check. +3 competence.

[Kurald Galain]

Fortunate Charm gives you a reroll.

Additional Traits feat lets you pick up traits like Focused Mind.

And I'm curious what your "various reasons" are, because generally speaking casters don't require a lot of gear or feats to pass their concentration checks.

[ezekielraiden]

Fortunate Charm gives you a reroll.

Additional Traits feat lets you pick up traits like Focused Mind.

And I'm curious what your "various reasons" are, because generally speaking casters don't require a lot of gear or feats to pass their concentration checks.

Partly, I'm gonna be going into melee a lot. Specifically tanking. That'll mean at least a few Defensive Casting checks, I'm sure, so I asked about them.

But the bigger share is checks induced by SoP drawbacks. They aren't Defensive Casting checks, so only generic concentration bonuses apply. Since PF is a labyrinth, I always assume I've missed something, meaning it never hurts to ask for tips. These checks scale slower than your CL, but getting an edge is still desirable. Drawbacks are and should be detrimental, I just want to manage them wisely.

[Xei_Win_Toh]

Will you be in melee together with a teammate? Convince them to pick up Shielded Caster (or Shield Sphere's Reassuring Imposition, if Spheres of Might is also allowed). Or if you have a cohort/eidolon/phantom/conjuration sphere/etc, those could also take them.

[Lirya]

Meditation (http://spheresofpower.wikidot.com/implements#toc61) implement special ability adds twice the enhancement bonus to Concentration checks with the spheres the implement applies to for only +1 000 gp.

[A.J.Gibson]

If you are in medium or heavy armor, Armored Casting (http://spheresofpower.wikidot.com/combat-feats#toc3) might be better than defensive casting.