Repulsion Runestone (similar to artificer infusion)
Resistance to a particular type
Absorbing runestone
Enlarge (Bonus AC at the cost of movement), maybe also bonus to nearby creatures
Ground spike, use a reaction to stop self being forcefully moved
Loyalty. shield returns to hand after throwing
Reflecting. When taking (elemental) damage, you can use a reaction to reduce the damage and then deal it (using an attack) to another creature in range
+1 Oversizing Runestone
wondrous item rare (requires attunement)
Shield/Armor Runestone.Usual text here
While holding this shield, you have a +1 bonus to AC. This bonus is in addition to the shield's normal bonus to AC.
Additionally, this runestone can allow the shield or set of armor to rapidly grow in size and weight. As a bonus action, you can enlarge the shield or set of armor for one minute, or until you end the effect with another bonus action. While enlarged in this way, the shield/armor grants an additional +2 bonus to your Armor Class but reduces your movement speed to 0.
Honestly could just reuse Oversized Shield from my pact of the shield
+1 Reflecting Runestone
wondrous item rare (requires attunement)
Shield/Armor Runestone.Usual text here
While holding this shield, you have a +1 bonus to AC. This bonus is in addition to the shield's normal bonus to AC.
Additionally, the runestone has 6 charges and regains 1d6 charges daily at dawn. When you take fire, lightning or radiant damage, you can expend one charge as a reaction to reduce the damage you take by 3d8. As part of the same reaction, you can spend one additional charge to make a ranged spell attack (spell attack modifier +7) against a creature you can see within 30 feet. On a hit, the creature takes the damage you reduced from the triggering damage.
mostly reaction defensive stuff
Ideas:
+1Oversizing Runestonewondrous item rare (requires attunement)
Shield/ArmorRunestone.Usual text hereWhile holding this shield, you have a
+1bonus to AC. This bonus is in addition to the shield's normal bonus to AC.Additionally, this runestone can allow the shield
or set of armorto rapidly grow in size and weight. As a bonus action, you can enlarge the shieldor set of armorfor one minute, or until you end the effect with another bonus action. While enlarged in this way, theshield/armorgrants an additional +2 bonus to your Armor Class but reduces your movement speed to 0.Honestly could just reuse Oversized Shield from my pact of the shield+1Reflecting Runestonewondrous item rare (requires attunement)
Shield/ArmorRunestone.Usual text hereWhile holding this shield, you have a
+1bonus to AC. This bonus is in addition to the shield's normal bonus to AC.Additionally, the runestone has
6charges and regains1d6charges daily at dawn. When you takefire, lightning or radiantdamage, you can expend one charge as a reaction to reduce the damage you take by3d8. As part of the same reaction, you can spend one additional charge to make a ranged spell attack (spell attack modifier +7) against a creature you can see within 30 feet. On a hit, the creature takes the damage you reduced from the triggering damage.