I hadn't found something like this for Tears of the Kingdom yet, so I decided to just make one.
If you're just after max stats, then it ultimately doesn't matter which wild horse you catch since you can just RAISE all stats to lv.5 by giving meals to the Horse God Malanya. Even the worst possible stats can be made perfect that way.
The only exceptions are the Giant Horses and Epona, which can't be upgraded - those stats stay the same forever.
However, it might still be beneficial to know which stats you can expect in different herds, because some of them are already pretty close to max right from the start (like for example the Wild 5245 in Group 08) which significantly cuts down the total upgrade cost since those meals can have some rare-ish, expensive ingredienst that are annoying to farm.
(my personal motivation for this however was that I dislike having too many icons on the screen and find horses with just 2 spurs perfect, but all online guides simply point out where the high stats and special horses are and flat-out ignore everything else)
The map does not show the locations of the special horses to avoid spoilers. If you want to find out where the Royal White Stallion, the Giant Horses, Spot or the Golden Horse are, you can find dozens of guides easily =P
Some more extra info:
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The group numbers are taken from the game code and correspond to the "WildHorseCreateTag" sections. WildHorseCreateTag04 and 07 exist but do not seem to have actual map placements, so there is nowhere for them to spawn.
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Some groups have "impossible" stat horses in the game data (like having a zero in a certain stat) but those horses do not seem to actually spawn for some reason. If anyone ever finds a regular horse that has a zero in any stat (except for the Giants and Epona which have zero Pull) please let me know, because as far as I can tell, you can not get Strength below 1 point or any other stat below 2 points. I have no idea why those stat combinations are still in the game code tho.
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One of these "impossible" horses is the "Default" horse, which had a unique coloration in BotW (brown body, white hoof tufts, dark muzzle and very dark hooves) and unique stats (4-3-3-0) but it does not spawn in the wild anymore in TotK. If you import an actual Default Horse from a BotW save file to TotK, it will turn into the "fake" variant (bright hooves, not unique) and get slightly different stats (4-3-3-3) instead.
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Spotted horses only appear after you finished the "Spotting Spot" quest, which in turn requires two completed temples.
For all other horse-related questions, consult HylianAngel's Horse Guide which is for Breath of the Wild, but still has accurate information for the most part since the devs didn't change much between this game and the sequel. Color combinations, temperament and the like are still the same.
If you have additonal information, questions or you spot a mistake, please let me know. If you post this elsewhere, please give proper credit and link back here, thanks.
There is also at least one major translation error that's only present in the English version. In the final boss battle, Zelda says that Ganon has "given up on reincarnation and assumed his pure enraged form", implying that the reincarnation cycle has been broken and there will be no more Ganons after this fight.
In all other languages including the original, it is some variation of "his obsessive refusal to give up on reincarnation turned him into this monstrosity", which implies the exact opposite. No matter how often you kill him, he just won't let go, ever - even if it means to turn into a mindless beast. He WILL try to survive and revive, no matter the cost.
I guess the translator in question got a little confused with the double negative (Ganon fiercely does NOT want to NOT reincarnate = he fiercely wants to reincarnate).