Heroes 5.5 WarGame Edition - Tactical Edition.

Considering such constant factors in the upgrade process as defense, attack bonus, and ranged attacks (50 damage), which impose certain limitations on the creature's and unit's hit points, and also taking into account the training, due to which the difference between adjacent Human tiers should be significant, I came to the following option:

(X/Y = basic increase / standard unit, the price of 1 creature in gold is indicated in parentheses)

TIER 1 (average standard 40 creatures per dragon)
14/56 goblin (100)
12/48 gremlin, fairy (125)
10/40 militia, imp (150)
12/36 skeleton (175)
10/30 guard (200)
6/24 assassin (250)

TIER 2 (average standard 24)
10/30 pikeman, zombie (200)
9/27 demon, gargoyle (225)
8/24 archer (250)
8/20 dancer (300)
6/18 shaman (350)
6/15 beast (400)

TIER 3 (average standard 15)
10/20 ghost (300)
8/20 berserker (300)
9/18 succubus (350)
6/15 swordsman, ogre (400)
8/12 hunter (500)
5/12 golem (500)
6/9 minotaur (700)

TIER 4 (average standard 10)
7/14 cerberus (450)
5/12 centaur (500)
5/10 monk, druid (600)
6/9 mage (700)
4/8 bear, predator (800)
3/6 vampire (1000)

TIER 5 (average standard 6)
4/8 priest (800)
5/7 nightmare, unicorn (900)
6/6 knight (1000)
4/6 witch (1000)
3/6 leader (1000)
4/4 djinn (1500)
3/4 lich (1500)

TIER 6 (average standard 3)
4/6 griffin (1000)
3/4 wyvern (1500)
3/3 reaper, rakshasa (2000)
2/3 balor (2000)
2/2 ent, than (3000)
1/2 hydra (3000)

TIER 7 (average standard 1.5)
1/2 necrodragon (2000 + 2m)
2/2 angel (2000 + 2c)
2/2 devil (2500 + m)
1/1 light/dark dragon (4000 + 4g/s)
1/1 titan, dwarf dragon, cyclops (5000 + 2g/s/c)

The number of creatures in tiers 1-3 was reduced, and in tiers 6-7 slightly increased.
The following ratio was adopted for the Knights: 40 militia = 24 archers = 15 swordsmen = 6 knights.

Informal division into a 4-level system:

TIER I
56 goblins (100)
48 gremlins, fairies (125)
40 militia, imps (150)
36 skeletons (175)
30 guards, pikemen, zombies (200)
27 demons, gargoyles (225)
24 assassins, archers (250)

TIER II
20 dancers, berserkers, ghosts (300)
18 succubi, shamans (350)
15 beasts, ogres, swordsmen (400)
14 cerberuses (450)
12 hunters, golems, centaurs (500)
10 monks, druids (600)

TIER III
9 minotaurs, mages (700)
8 bears, predators, priests (800)
7 nightmares, unicorns (900)
6 vampires, knights, leaders, witches, griffins (1000)
4 liches, djinns, wyverns (1500)

TIER IV
3 balors, reapers, rakshasas (2000)
2 hydras, ents, thans, angels, devils, necrodragons (2000-3000)
1 light/dark/dwarf dragon, titan, cyclops (4000-5000)