A friend of mine is starting up an offline campaign using D&D 3.5, a system I haven't used for anything in nearly five years, but that I played from 2003-2009 pretty regularly, and only stopped playing completely in mid-2012. I'm going to be playing a diviner. If you've played much D&D 3.5 as a spellcaster (especially an arcane one), you probably know that divination is the smallest school with the biggest gaps in its capabilities, which means any smart diviner player should spend a bit of time in character on spell research. I can't find my old 3.5 notes (long since thrown out, I suspect), so here are some ideas I've had for spells over the years that I still remember. Some of them are slightly better than similar spells in the PHB II in particular (which had a bunch of really terrible divination spells in it) though nothing's a straight copy of anything I've seen anywhere else. A bunch of them are more useful for social stuff and roleplaying than for dungeon exploration per se. This list goes up to 5th level here, I'm still doing some thinking around higher-level divinations.
Cantrips (0th level):
Count - Medium range, 1 standard action, instant, V, S. Caster receives a count of all objects of a specified type within range. Does not reveal location or distance, only presence
The Time - Self range, 1 standard action, instant, V. The caster knows what time it is, using whatever measurement method is most meaningful to them.
Weatherman - Special, 1 standard action, instant, V, S. Caster knows what the natural weather will be like within a cylinder 1 mile in radius / level and centred on them, up to a number of days in the future equal to their level.
Calculate - Touch range, 1 standard action, instant, V, S. The caster touches a proposition or equation previously written down in a formal notation, and the correct answer or derivation appears below or beside it. The spell does not supply more information than was initially given - undefined variables remain variables, while supplying actual values produces an answer with the same.
Collapsing Favour - Medium range, 1 standard action, # of rounds = level, V, S, M. Designate a target (save allowed). Every missed attack on that target by the caster or their allies after the spell is cast grants a cumulative +1 insight bonus to hit and damage to all further attacks against it until it's hit by an attack. (e.g. one attack missed means +1, two missed attacks means +2, etc.) The material component is an albatross feather
Detect Life - Close range, 1 standard action, 1 round / level V, S, M.The caster can detect lifeforms of Tiny-size or larger within a 90-degree cone up to the range of the spell. By concentrating for one round, the caster can determine either number or the types, and may spend a second round to determine the other.
Flash of Insight - Self range, 1 standard action, instant, V. +10 insight bonus on one Knowledge check (even if not trained in it) or one Sense Motive check.
Greatest Fear - Close range, 1 standard action, concentration, V, S. Spend 1 round to discover the greatest fear or concern a sentient creature has (save allowed). Can shift to a new creature each round, max # of creatures scanned = level.
Heart's Desire - Close range, 1 standard action, concentration V, S. Spend 1 round to discover the thing a sentient creature wants most (save allowed). Can shift to a new creature each round, max # of creatures scanned = level.
Liar's Tremble - Close range, 1 standard action, 1 turn per level, V, S, M. The caster asks the target one question (it may save) in a language it understands. It must either answer the question truthfully and correctly, or be dazed until the end of the spell. The question does not need to be one it can reasonably be expected to know the answer to. The material component is a
Greater Flash of Insight - Self range, 1 standard action, instant, V. +20 insight bonus on any one Knowledge check (even if not trained in it) or one Sense Motive check.
Penetrating Vision - Close range, 1 standard action, concentration. The caster can see through inanimate objects within a 45-degree cone (magical objects may save). If more than one intervening barrier or object is within the area of effect, the caster may choose to "tune" the spell each round to only render some transparent, allowing them to read the pages of a closed book, examine the contents of a sealed chest, or book. Creatures may save to avoid having their personal equipment penetrated. Caster has line of sight but not necessarily line of effect to any creatures revealed, and the area revealed is not lit by the spell.
Darkvision, Mass - Touch, 1 standard action, 1 hour / level. The caster and up to 1 ally / per level that they touch when casting the spell has darkvision to 60' until the spell ends.
Decrypt - Touch, 1 full-round action, 1 page or inscription / level. The caster touches a piece of coded writing, and the text appears in their mind decoded. This spell does not translate the writing.
Retrocognition - Close range, 1 full-round action, concentration. [Scrying] The caster names a time in the past and receives a vision of what happened at their present location from that point forward, for as long as they concentrate, in real time. i.e. Concentrating for one round shows one round, concentrating for one turn shows one turn. Every minute watched requires a concentration check, starting at DC 10 and adding +5 for each additional minute that has passed. The vision includes auditory, olfactory, and visual components.
Psychometry - Touch, 1 full-round action, 1 question / level. The caster handles an inanimate object and is able to derive insight into its past. They may ask one question per caster level about the object's history (i.e. its place of creation, its age, or prior shapes it may have had), about the object's owners (i.e. how many it has had, who its last owner was, etc.) or about events it was directly involved in (i.e. a dagger about a murder it was used it). The answer to any given questions is either a short single sentence or a brief dreamy vision (DM's choice).
Analyse Material - Close range, 1 standard action, instant. The caster knows the composition and properties of the substance of any one object within range. This information is as detailed as the technical knowledge of the caster allows. A caster with knowledge of the periodic table would receive a molecular breakdown as part of their knowledge, while one with an Empedoclean conception of physics would understand it in those terms. The caster also learns whether the substance is poisonous, alive, magical (but not the details of the enchantment), radioactive, etc.
Architect's Bane - Long range, 1 full-round action, instant. The caster points at one building and receives a vision of its layout accurate enough to draw maps from. Only permanent physical features of the building (its walls, roof, fountains, etc.) are shown, not furniture or inhabitants. This knowledge includes secret doors and compartments. It will not show an area warded against divination, encased in 1" or more of lead, or any area containing an anti-magic shell.