Best unit for the price.

The Heroes series had a significant impact on me, largely due to the incredibly diverse and impressive array of units; it's hard to pick just one. First

1. Sprites. Such amusing little ladies, hands on their hips, lol.
2. Phoenixes. There's something beautiful about these plucked chickens.
3. Dragons. Aren't they cute! Pink and purple dragons from a fairy tale, as if Spike from My Little Pony dropped by for a visit.
4. Rogues. OG elementals of exhibitionism; the attack animation is especially funny.
5. Djinn. Just appreciate how he sits on the carpet; it's incredibly colorful.

Second

1. Pigs. Just pigs. What logic led them to the wizard's castle? So many questions, so few answers.
2. Wolves. A wolf is a wolf, to be a wolf, you must be a wolf, you are not you when you are a wolf. Awooo.
3. Dragons. Three grades. Three far-off grades. Yo dawg, I heard you like upgrades, so we added an upgrade to your upgrade, so you can upgrade your units while you're upgrading your units...
4. Ogres. Why do they have ram heads?
5. Unicorns. Incredibly beautiful artwork.
6. Phoenixes. I think they are one of the most beautiful units, not just in the second game, but in the entire series. They shimmer so beautifully.

Third

1. Griffins. This is where I step onto the path of nostalgia; I remember griffins from childhood.
2. Nagas. No, but these are waifu material; I adored them.
3. Djinn. Ungraded ones are almost as much waifu material as the nagas.
4. Cerberuses. Doggies, everyone loves doggies; I like doggies.
5. Gorgons. Far, far away, on a meadow, graze the... This unit is not only an uber-meme but also cool.
6. Pegasi. Oh, there are naked ladies flying on horses; I should go take a look; I haven't seen horses in a while...
7. Unicorns. Almost as beautiful as in the second game.
8. Manticores. Kitties! I've loved manticores since then; they're one of my favorite monsters of all time.
9. Black Knights. These are Nazgûl! I was obsessed with Lord of the Rings at the time.
10. Monsters. Hippos! I was a little scared of them as a child; now I adore them.
11. Sprites. No, but these are also waifu material; they're beautiful.
12. Water Elementals. Stay with us, boy.
13. Elementals of exhibitionism, just elementals of exhibitionism.
14. Dragons, whether black, gold, or neutral, are all good. The magic ones, the dragon-sprites, are especially memorable.

Fourth

1. Djinn. They became even more beautiful than in the third game, and now they don't change gender, yay!
2. Vampires. No, but these are crush material, this is husband material. Such gentlemen.
3. Nightmares. Horses! No, not quite. HORSES!!!
4. Hydras. They stomp on two legs very funnily.
5. Wolves. Awooo. Besides the memes, I love wolves even apart from the terrible memes; they are very beautiful and intelligent animals.
6. Tigers. KITTIES!!!!! Love at first sight, oh my gosh, my first reaction was, what, was it possible to just make a big, beautiful cat a unit???
7. Unicorns. Rainbow! I can't help it; I love rainbows. Rainbow Dash is the best pony.
8. Mantises. My favorite unit in the game; I was amazed the first time I saw an insectoid the size of a dragon, and I'm still amazed.
9. Thunderbirds. These are really thunderbirds, not overgrown eagles!
10. Sorceresses. A chic design, very ominous and unusual.
11. And again, dragons. Magic and black ones, especially. I think the local black ones are the most beautiful dragons in the series.

Fifth

1. Gargoyles. Everyone's favorite uber-meme tumblers, a legend, and my love; I adore them, the best design, and this isn't even sarcasm. Anyone can draw a winged, horned, demon-like gargoyle, but a far-flying tumbler...
2. Djinn. Wow and mind-blowing. A very cool and unusual design; the giant hands and lack of a head are simply a brilliant design solution, and again, without sarcasm, I love the alien and unusual.
3. Rakshasas. I have to admit, I used to be a furry, if anyone didn't know. I don't even know which version I like more, the cute, un-upgraded ones or the powerful, upgraded ones. One of the units that blew my mind.
4. Beasts. No, but these are waifu material. There was a period in my life when I was into cool girls in bikini armor, but I don't know if my love for similar units in the fifth game is the cause or the result of that period.
5. Riders on evil lizards. What, was that possible?!
6. Witches. No, but these are ultimate waifu material.
7. Angels. What difference does it make what gender they are if they are beautiful?
8. Succubi. No, but these are top-tier waifu material; I adore the local succubi; half of my avatars had horns and hooves. Because of them, I at least started looking at demons, and Disciples came later, I think.
9. Nightmares. Horses!!!
10. Vampires. No, but these are husband material.
11. Undead. Mind-blowing, a death with a scythe on the battlefield, wow.
12. Sprites. Another "What, was that possible?", after which the second half of my avatars got vines, creepers, and flowers all over their bodies.
13. Wardancers. No, but these are ultimate husband material and crush material. Usually, I talk about the unit as a whole, considering all upgrades as one unit, but here I will note the wardancers, the first upgrade 😍
14. Druids. I feel sorry for the deer
15. Unicorns. Such powerful horses!!!
16. Ents. I love their alienness.
17. Bear Riders. I don't like dwarves, but the bear cavalry won my heart.
18. Shamans. Another waifu, yes.
19. Phoenixes. Beautiful, graceful, and dragon-like.

Sixth

1. Demon Matrons. I felt a connection to Disciples; I love the chthonic.
2. Juggernauts. They have a beautiful name and a cool design.
3. Glimmers/light elementals. Waifu.
4. Harpies. Cool birds.
5. Kirins. A Chinese imitation of dragons.
6. Manticores. No, but these are kitties.
7. Spider Ladies. They are chic; I've loved arachno-centaurs since Oblivion, I think? Spiders are creepy in themselves; I adore these creatures, as long as they don't crawl on my pillow, of course.
8. Lamassu. Cats are cats, even if they're not fresh.

Seventh

1. Deer. Removing unicorns from the lineup of the elven faction is heresy of the eighty-level, but the little deer are still cute.
2. Mages. Like in the good old days of the first game, they ride carpets.
3. Justiciars. I just love warrior women; I see a warrior woman, I give it a like.
4. Pixies and Dryads. My love for gentle, natural girls has never gone away.
5. Basilisks and Hippos. I'm glad you're back, guys, even if it's in such a crappy part of the game.

I didn't play the seventh game much; many of the designs caught my eye primarily from the announcements. In the game itself, they look much worse than in the promo, due to the overall dull visuals and recoloring to the player's color. And it's obvious that the designers of the fifth game earned their bread for a reason; many of them appeal to me. If I had to choose one unit per part, it would probably be:

1. Djinn
2. Phoenixes
3. Manticores
4. Mantises and white tigers (I refuse to choose one of them)
5. Succubi, sprites, and rakshasas (I also refuse to choose)
6. Spider Ladies
7. Deer