TLDR; It would be cool if primary domains didn't override secondary domain on summon themes even if secondary domain is chosen first in creation/selection, wouldn't be bad either I feel if more primary domains were added too. Read on for specifics for that at the bottom
A few suggestions and some feedback having been playing a cleric myself as well, for a few various deities, it can be a bit hard to find a primary domain that.. fits necessarily, that isn't going to A: Jack up the summon theme you want for secondary if any, as summon theme from primary overrides secondary, even if you chose secondary first.
And just changing that alone would be pretty nice, so you get the summon theme you intend for, rather than remaking and choosing an alternate domain that won't do so even if it fits less. Example: I am playing a cleric of pitter peter currently, after a few trial runs, I really learned a lot i'd say @_@ BUT! I settled on Knowledge/Ooze instead of Earth/Ooze as I'd have preferred, not only for the drastic difference in turn capability and power, but also because knowledge doesn't override the ooze theme like earth does, and while finding tomes is always an option, I've yet to come across a single tome on any pc that isn't a few select themes, they exist, but sometimes, you don't want to have to wait to find an item to hold more true to your concept. And bothering DM's for a summon theme change feels very disruptive to me.
Knowledge is the only primary pitter peter domain additionally, and I'm unsure on domain choices outside of their listed range despite being relic guardians still, but even if I can as I believe, chaos was the only one that would make sense beyond earth, and chaos isn't really the focus of the character so much.
Domain Talk!:
And definitely more primary domains, I understand the need to have primary domains be a bit shorter in listing because just as the longer list of secondaries keeps from pairings of certain domains, too many primary domains would also mean fewer pairings of other kinds. But a small suggestion to encourage people to start to move on to the growing and very nice list of city deities possibly (If that's even wanted) or to emphasize the fact that their presence is felt or there in some way or another enough to be a established faith in the city, maybe allow, given the relic guardian is a priest of a city deity only from the start, that the list of domain choices for city deities be expanded into allowing multiple primary domains but ONLY the additional listed primary domains permitted to that deity to function as a secondary option, and in that case, they gain the turn undead only of the first primary chosen, and cannot choose primary domains as a secondary outside of the primary ones listed. In spirit of relic guardian, it could be cool to allow a different primary domain option than the listed ones as the first choice than the one's from their list, of course given it makes sense and isn't just rpless and shameless powerbuiding.
Primary Domain Possible Suggestions:
Animal (Animal focused deities), War (War and combat focused deities), Trade (Trade deities, phanaxians come to mind, that would be a certain primary for him), Nobility (I see many peerage opportunities), Plant, (Another very common nature-esq deity primary) Protection (Tbh just got a cool idea for this one, though i could see a few potential faiths for it)
Turn Undeads!
[
b]Animal Turn Undead:[/b]
-Bestial Frenzy: The caster, all animals, and allies within the area of effect are induced with bestial rage, gaining blood frenzy for 1 turn+1 round/cha modifier, and 10% movement speed, allies are given a will saving throw to avoid these effects (DC: lets say, 15+Cha Modifier?)
-Hunger Of The Beast: The caster and all allies, and animals within the area of effect gain vampiric regeneration 2+cha modifier/2 for a 1 turn+1 round/cha modifier
-Strength Of The Wild: The caster, all allies, and animals within the area of effect gain +2 str, dex, con, endure elements at the casters level for 1 turn+1 round/cha modifier
Optional: Omit allies from these effects if too OP, so only caster and animals are effected
War Turn Undead:
-Master Of Arms: For 1 Turn per level/2 caster and all allies in area of effect gain proficiency, weapon focus, and weapon specialization in all weapons (Optionally: +1 Enhancement, +d4 damage of weapon type applied to weapons in hand for all allies and caster in area of effect for 1 Turn per level/2)
-War Cry: All Allies and caster in area of effect gain 10 temporary HP, +1 AB, and 10% movement speed, enemies in area of effect must make a will save (DC: 10+cha modifier) or lose 1 AB and 10% movement speed. These effects last for d4 Rounds+1 round/cha modifier
-Stamina Of The Warlord: Caster and all allies gain +20% movement speed and +2 con for 1 Turn+1 round/cha modifier
Trade (Yup, Trade)
-Eye For Value: The Caster And All Allies within the area of effect gain +5 lore, appraise, search, spot, AND listen for 1 Turn+1 turn per level/2
-Lucky Finds!: All -humanoid races only- (Human, bugbear, lizardfolk, elf, dwarf, ect.) enemies hit with the trade domain turn undead will gain a d4 gold pieces that drop upon death
-Fortune Favors The Bold: The caster ,and all allies receive +1 to all saving throws with an additional +1 per cha modifier/2 (Capped at +3 total bonus) For d4 rounds+1 round/level
Nobility Turn Undead:
-Aura Of Regality: Caster and all allies in area of effect gain +2 cha, +2 persuade, intimidate, bluff, and a reroll on failed related checks for 1 Turn+1 Turn per level/2
-A Leaders Presence: Creates a aura that follows the caster, all allies (only, not the caster, or enemies) within the area of effect are inspired gaining the benefits of a battletide spell, enemies do not suffer the penalties of battletide by entering the aura.
-Lead The Charge!: The caster and all allies gain +50% movement speed for a d4 rounds+1round/level
Plant:
-Reclamation Of The Wild: Centered upon the caster, an entangle, grease, and stinking cloud are created with the caster gaining temporary immunity to all three, the immunity and spells lasting for 1 round/level of caster
-Strength Of The Wood: The caster, all allies, and any plant type enemies/allies in the area of effect gain the benefits of a barkskin spell at the casters level for 1 turn+1 round/cha modifier
-Wreath Of Thorns: The caster, all allies, and any plant type allies/enemies in the area of effect gain a d4 piercing damage shield and DR 5 Slashing/Bludgeoning for a d4 rounds+1 round/cha modifier
Protection:
-Gaurdians Stance: The caster and all allies in the area of effect gain +1 Dodge AC +1/cha modifier (Capped at +3) and immunity to knockdown and slow for d4 rounds+1/cha modifier
-Skin Of Steel: The caster and all allies in the area of effect gain 10 DR/+1 for d3 round+1/level
-A Protectors Duty: All allies in the area of effect gain +1 regeneration for 1 Turn and should any allies fall within that time effected by the turn undead, they will instead be healed for 2d8+10 and the caster will in turn take that amount of damage each time any ally should fall up to a total of 1 ally per charisma modifier (this is uber complicated I know scripting wise, so alternatively!: 1 regen+1/cha modifier (Capped at 3) for 1 Turn)
hope yall like the ideas!