(Sorry if this is repeat information)
But if you go onto the magic screen, hold ALT and press R V L it 'reveals' the whole map on both planes for you.
I think that this is a particularly 'good' cheat as it allows you to plan ahead, refine your strategy and gives you a good head start without ruining the game, for example being able to win any battle, unlimited resources etc.
Some games (I hesitate to mention Heroes of Might and Magic series) have cheats that will often diminish or destroy your enjoyment of them.
Some wag will probably post "then don't use them!", but I get frustrated after 8+ hours of play and careful planning ruined by the computer pulling a fast one.

Welcome to the madhouse. As a suggestion for next time, I'd recommend adding SPOILERS to the thread title, just as an extra heads-up. (No harm no foul, though, at least from me.)

The upside of this exploit is that it casts both Nature's Awareness (an otherwise very rare Nature spell) and Detect Magic (an uncommon Arcane spell).

The downside is that it does the same for the other wizards as well, putting them in touch with you right away. And these two spells have a per-turn maintenance cost, which you'll be paying unless and until you dispel them. Not all that critical after the first few turns, but a potential disaster early on when mana resources are still low.

My favorite use of this exploit:

1) Generate a new game. Before starting play, save it to a save slot.

2) Use the cheat code, and see if the selection of wizards, cities, races and available resources makes for a game you want to play.

3) If so, restart the game by reloading from the save slot and play as normal. (You can always redo the exploit mid-game if you feel the need.)

4) Profit.

Thank you kindly for the welcome and useful advice, and your recommendation is how I use the cheat.
I like to play humans because of the Paladins, and these take a long time to build, as I'm sure you know. It's therefore important to know who your neighbours are, and how likely they are to attack you before you're ready. Often I'll re-start the map generator until I'm alone on a continent with at least one tower so I can build at leisure and start my campaign 'upstairs' when I'm ready.

I think I will try this. I often play 50+ turns in a game only to find the terrain layout and enemy starting positions just suck, and start all over. I'm not much for cheat codes, but this would essentially be doing what I do anyway, just quicker.

As far as building paladin armies goes, I find it easier to start with some other race than high men, then conquer a high man neutral or enemy city to build paladins. The trouble with high men is they don't have any really good units until you reach the end game paladins and magicians. Start with halflings, high elves, or barbarians. They all have good relations with high men so conquered cities aren't hard to manage. But these races have effective troops with much more modest prerequisites: halfling slingers, high elf cavalry and longbows, barbarian cavalry and berserkers. A single barbarian cavalry can capture most neutral cities by itself. The elf cavalry isn't as good but will do the job if you cast a few booster spells on it.

Thanks for that tip!
When I've tried another race to capture a human city in the past I've tended to use the Klackons (because of the quick-to-build and tough Stag Beetle) which meant my human subjects were pretty soon revolting (to coin a phrase), I'd never contemplated using a friendlier race before.

Two other very fast, nice races are nomads and gnolls; both only need to add a stable to start making decent units (a fighter's guild, naturally, will make the units better right out of the gate). Nomad horsebowmen trade in the first strike of normal cavalry for 8 ranged shots, and with 2 move they can kite a lot of units while shooting with no range penalty. They also have a decent melee attack once the arrows run out. Nomad's can later follow up with Rangers for lots of mobility (2 move pathfinding) from a decent unit.

Gnoll wolfriders are insanely fast (3 move!) and hit very hard for how early you can get them. They don't have a lot of shields, but they do have a decent number of hp. And they are crazy cheap. You can get 3.2 wolfriders for the cost of 2 stag beetles, and you can start churning out wolfriders with just a barracks and a stable. Not to mention that it doesn't take a gnoll city long until the most useful thing they do is churn out more wolfriders, which can then get to where you need them pretty quickly (if you have a way to cross intervening water, at least).

Protip: racial tension is NOT based on which units are garrisoned within a city, but instead which city your Wizard's Fortress is in. If your subjects don't like you, you can change your starting race either by casting the rare Nature spell Move Fortress, or (if necessary) by your choice of which city you re-establish yourself upon casting the Spell of Return.

The hive mind Klackons hate everyone (except themselves) equally, while other races — Dark Elves, for example — range from blatant intolerance to outright xenophobia. Halflings, Nomads and High Men are the most tolerant, while Gnolls, Barbarians and (somewhat surprisingly) Orcs are up there as well.

The problem with choosing a race to start with that's not the same as the race that has the units you want is that you can never be sure there will be even one city for you to conquer and exploit. You might start with halflings and find only orcs, gnolls, and nomads on Arcanus. No paladins for you.

Very true. Usually you can find SOME race that can fill roughly the same function, but when only Dark Elves will do, and there ARE no Dark Elves...

Thus using the cheat code described at the start of this thread to scout the world before playing turn 1. Though honestly high men are very common. While occasionally you see a world without high men neutral cities, I have never seen one that didn't have either high men neutrals or high men opponents.

I have.

In fact, I've seen all kinds of strange outlier outcomes: Myrror with no adamantium and nothing but draconian neutrals; or Arcanus where every rival wizard has gnolls and the only non-gnoll neutrals are high elves. I've even seen Arcanus with no mithril deposits at all.

Sounds like a good strategy for a relaxing game.

My favorite cheat/exploit was using the "Plane" toggle and moving using the numpad to pick my units direction.
For a brief moment your unit is actually in the other plane (it can launch attacks on the other plane and bypass the defenders of nodes, keeping them perfectly intact to defend your melded node.)

I like seeing how long I can last on Impossible with this as my only supplement to offset the fact that they still have much more Spell Power than I until I get my Flying Halfling Slingers with Magic Immunity wreaking havoc across their cities.