My favorite effect is Control Weather to suit the weather to the ruler's desires. Yes, it is high-level, but with such a large area the entire city will only need one casting.
I have written
two articles about this, but I am afraid they are quite old and not very good.

Allow me to post the spells I have identified as important (3E) from the first article:
Alarm: Brd 1, Rgr 1, Sor/Wiz 1, 25 ft. radius, 2 hours/level
Animal Friendship: Drd 1, Rgr 1, HD=2x caster level
Animal Messanger: Clr 2, Drd 2, Rgr 2 1 day/level
Animate Dead: Clr 3, Death 3, Sor/Wiz 5 2 HD x caster level (50 gp/corpse)
Arcane Lock: Sor/Wiz 2 Permanent (25 gp)
Atonement: Clr 5, Drd 5 (500 gp focus, 500 XP)
Awaken: Drd 5 Instantenous, Tree of Animal (250 XP)
Bless Water: Clr 1, Pal 1 Instatenous (25 gp)
Break Enchantment: Brd 4, Clr 5, Luck 5
Clairaudience/Clairvoyance: Brd 3, Knowledge 3, Sor/Wiz 3 Lead sheeting blocks it
Command Plants: Drd 8, Plant 8 1 day/level on plant creatures, HD=3 x caster level
Commune: Clr 5 (Holy Water&Incense, 100 XP) One question per character level
Commune with Nature: Drd 5, Animal 5 1 mile/level, 3 facts
Comprehend Languages: Clr 1, Wiz/Sor 1
Consecrate: Clr 2(Holy Water + 25 gp) 20’ radius, 2hours/level
Contact Other Plane: Brd 5, Sor/Wiz 5 1 question/2 levels
Continual Flame: Clr 3, Sor/Wiz 2 Torch-equivalent (50 gp)
Control Water: Brd 5, Clr 4, Sor/Wiz 6, Water 4 10 min/level, 10’/level x 10’ /level x 2’ /level
Control Weather: Air 7, Brd 6, Clr 7, Drd 7, Sor/Wiz 6 4d12 hours, 2 mile radius
Create Food and Water: Clr 3 24 hours, 3 humans/level for one day
Create (Greater) Undead: Clr 6, Death 6, Evil 6 / Clr 8, Death 8 Controlled through Turn Undead (Misc + 50 gp/HD/corpse)
Create Water: Clr 0, Drd 0, Pal 1 2 gallons/level
Cure (something) Wounds: Brd, Clr, Drd, Healing, Pal, Rgr
Curse Water: Clr 1 (25 gp) Affect good outsiders as blessed water affects undead
Demand: Sor/Wiz 8 (arcane connection) Arcane connection, as sending + suggestion
Desecreate: Clr 2, Evil 2 2 hours/level, 20’ radius (unholy water+ 25 gp)
Detect Evil: Clr 1, Rgr 1, Pal unlimited 60’, up to 10 minutes, a lot of matter or thin lead sheet block it
Detect Magic: Brd 0, Clr 0, Drd 0, Sor/Wiz 0
Detect Scrying: Brd 4, Sor/Wiz 4 120’ radius, 24 hours
Detect Thoughts: Brd 2, Knowledge 2, Sor/Wiz 2 60’, up to 1 min/level
Detect Undead: Clr 1, Pal 1, Sor/Wiz 1
Discern Lies: Clr 4, Pal 3 1 round/level, one subject at a time
Discern Location: Clr 8, Knowlegde 8, Sor/Wiz 8 Overcomes all barriers
Dismissal: Brd 4, Clr 4, Sor/Wiz 5
Dispel Evil: Clr 5, Good 5, Pal 4
Dispel Magic: Brd 3, Clr 3, Drd 4, Magic 3, Pal 3, Sor/Wiz 3 D20+caster level (max 10) vs DC 11 + caster level.
Divination: Clr 4, Knowledge 4 Within 1 week (25+ gp)
Dominate Person: Brd 4, Sor/Wiz 5 1 day/level, Will negates
Dream: Brd 5, Sor/Wiz 5
Endure Elements: Clr 1, Drd 1, Pal 1, Sor/Wiz 1, Strength 1, Sun 1 1 creature, 24 hours
Explosive Runes: Sor/Wiz 3
Fabricate: Sor/Wiz 5
False Vision: Brd 5, Sor/Wiz 5, Trickery 5 Radius=25’+5’/level, 1 min./level (250 gp)
Fire Trap: Drd 2, Sor/Wiz 4 When opens something (25 gp)
Flesh to Stone: Sor/Wiz 6
Forbiddance: Clr 6 60’ cube/level, Permanent, alignement & instant transport blocked, or password (1500+5000 gp/cube)
Gentle Repose: Clr 2, Sor/Wiz 3 1 day/level
Glyph of Warding: Clr 3 (incense + 200 gp) Pass phrase, type, alignemnt etc., 1d8/2 caster level hp or 3rd level spell
Goodberry: Drd 1 1 day/level, 2d4 normal meals + 1 hp (max 8)
Greater Glyph of Warding: Clr 6 10d6 or 6th level spell (400 gp + incense)
Greater Scrying: Brd 6, Clr 7, Drd 7, Sor/Wiz 7 1 hour/level,
Guards and Wards: Sor/Wiz 6 (misc + umber hulk blood) 200 sq ft/level, 2 hours / level
Guidance: Clr 0, Drd 0 +1 to skill check
Hallow: Clr 5, Drd 5 (1,000 gp + 1,000 gp/spell-level) 10’/level radius, Inst., as magic circle against evil + undead. One year can apply another spell, including: Daylight, detect evil, detect magic, dimensional anchor, discern lies, dispel magic, endure elements, invisibility purge, tongues, silence, zone of truth.
Imp. Invisibility: Brd 4, Sor/Wiz 4
Invisibility: Brd 2, Sor/Wiz 2, Trickery 2
Invisibility Purge: Clr 3 1 min/level, 5’ radius/level
Ironwood: Drd 6 1 day/level
Knock: Sor/Wiz 2
Magic Jar: Sor/Wiz 5 (100 gp Focus)
Magic Mouth: Brd 2, Sor/Wiz 2
Make Whole: Clr 2
Mark of Justice: Clr 5
Mass charm: Sor/Wiz 8 1 Day/level, HD=2 x level
Mending: Brd 0, Clr 0, Drd 0, Sor/Wiz 0
Misdirection: Brd 2, Sor/Wiz 2 Detect target another, 1 hour/level
Nondetection: Rgr 4, Sor/Wiz 3, Trickery 3 Hard to detect or scry, 1 hour/level (50 gp)
Obscure Object: Brd 2, Clr 3, Sor/Wiz 2 (chameleon skin) hides from location by a spell, 100 lb/lvel, 8 hours
Passwall: Sor/Wiz 5 1’’ per level, blocked by metal
Permamency: Sor/Wiz 5 Includes alarm (500 XP), magic mouth (1000 XP), phase door (3500 XP), prismatic sphere (4500 XP), symbol (4000 XP+10000 gp),
teleportation circle (4500 XP +1000 gp), wall of fire (2000 XP), wall of force (2500 XP)
Plant Growth: Drd 3, Plant 3, Rgr 3 Inst., ½ mile enrichment, overgrowth 100’
Purify Food and Drink: Cle 0, Drd 0 1cu ft/level
Quench: Drd 4
Raise Dead: Clr 5 (500 gp)
Reincanrnate: Drd 4
Remove Blindness/Deafness: Clr 3, Pal 3
Remove Curse: Brd 3, Clr 3, Sor/Wiz 4
Remove Disease: Brd 3, Clr 3, Drd 3, Rgr 3, Pal ability
Scrying: Brd 3, Clr 5, Drd 4, Sor/Wiz 4 (0 drd, 100 clr, 1000 wiz gp focus)
See Invisibility: Brd 2, Sor/Wiz 2 10 min/level
Sending: Clr 4, Sor/Wiz 5 25 words, anywhere
Sequester: Sor/Wis 7 Oen object, up to 2-ft cube per level, 1 day/level, invisibility+unscrying
Soften Earh and Stone: Drd 2, Earth 2 10’ sq./level (1-4’ deep), Inst., undresed stone only
Speak with Animals: Clr 2, Drd 2, Rgr 1 1 min/level,
Speak with Dead: Clr 3 1 min/level, 10’ to corpse, 1 q/2 caster levels, body must still have mouth
Speak with Plants: Clr 3, Drd 3, Rge 2 1 min/level
Stone Shape: Clr 3, Drd 3, Earth 3, Sor/Wiz 5 Inst., 10’ cu. + 1/level, crude shape only
Stone Tell: Clr 6
Symbol: Clr 8, Wiz/Sor 8 (10000 gp if lengthy) Includes password, attune individuals, alignment or actions. Guards portal or “reading”, 60’, opt of Permamence Death 150 hp, Discord, Fear 10 min/level, insanity, pain, persuation, sleep, stunning
Teleport: Sor/Wiz 5, Travel 5
Teleportation Circle: Sor/Wiz 9 (1000 gp) 10 min/level, without error
Telepoty Without Error: sor/Wiz 7, Travel 7 (1000 gp)
Temporal Stasis: Sor/Wiz 9(5000 gp)
Tonguews: Brd 2, Clr 4, Sor/Wiz 3 (small caly model)
Transmute Mud to Rock: Drd 5, Sor/Wiz 5 2 10’ cubes/level, perm
Transport via Plants: Drd 6 Any distance to same plant species
Tree Stride: Drd 5, Rgr 4 1 hour/level, teleport from tree to tree, limited but large range (6miles at 10 level)
Undetectable Alignment: Brd 2, Clr 2, Pal 2 24 hours
Wall of Iron: Sor/Wiz 5(50.x gp) Inst., 5’ sq./level, 1”(&30 hp 10 hardness)/4 caster levels
Wall of Stone: Clr 5, Drd 6, Earth 5, Sor/Wiz 5 Inst., 5’ sq./level, 1” (& 15 hp, 8 hardness)/4 caster levels
Whispering Wind: Brd 2, Sor/Wiz 2 1 mile/10 minutes, 25 words, 1hour/level
Zone of Truth: Clr 2 5’ radius/level, 1min/levelmmun