I'm going to pick a favorite and least favorite Robot Master from each game in the original series, and probably do MMX Mavericks later.
MM1 Best: Elec Man. Man looks like a damn superhero. Iceman is honorable mention because he's just doin' his best.
MM1 Worst: Fire Man. Man does exactly the opposite of his job title. Looks cool, though.
MM2 Best: Air Man. This dude was like "Yeah, you all have strong powers. I'mma be a menace with a FAN." Then he ended up looking the coolest, too.
MM2 Worst: Flash Man. This even suppose to be? He's just Jay Leno in a robot suit. What's "flash" about this? Terrible.
MM3 Best: Needle Man. The man is horrifying. He specializes in NEEDLES. That's some sick shit, I love it. Gemini Man has the coolest fighting, though... and like Snake Man is awesome. Respect to Top Man for representing a damn top of all things and actually dressing that way
MM3 Worst: Hard Man. Bruh. Dude specializes in... hardness. All he does is fist people and look like a barrel. Dishonorable mention is Top Man because... look at him. He's Top Man.
MM4 Best: Dust Man. Not only is he the coolest looking ventilation shaft I have EVER seen, the man might be the most unhinged of all the robot masters. He is specializes for torturing humans. The man uses DUST. That's not... that isn't going to beat robots! He's attacking peoples' ALLERGIES! Honorable mentions are Ring Man, Pharaoh Man, Toad Man, and Skull Man... because I like them.
MM4 Worst: Bright Man... Look at him.
MM5 Best: Napalm Man. Do I need to explain this? LOOK AT-... LISTEN TO HIS NAME! Honorable mentions to Wave Man for looking super cool and Star Man for being the dude who was like "My power's gonna be throwing STARS at people." Like... come on.
MM5 Worst: Charge Man. THE MAN IS DRESSED AS A CHOO-CHOO, HE NEEDS A GUARDIAN!
MM6 Best: Knight Man. He looks cool and he's a neat idea. Honorable mention is Yamato Man because he's basically just Knight Man's eastern cousin. Oh, and Blizzard Man. Like... he's stupid, but I like the kind of stupid he is.
MM6 Worst: The rest of them. They're... they're all just so bad. Look at them. LOOK.AT.THEM.! Like there's just no inspiration here, they're all so stupid or generic. Wind Man is JUST AIR MAN AGAIN! Flame Man and Tomahawk Man are hate crimes. Plant Man.
MM7 Best: Freeze Man is cool looking and Junk Man is pretty unique. Turbo Man gets points for being a literal transformer.
MM7 Worst: Bass. Also Spring Man, but I like him anyway. Oh, and Turbo Man. BECAUSE THAT IS NOT TURBO MAN!
MM8 Best: This is going to be a hot take, but I love almost all of them. Clown Man is PEAK design and so fucking unhinged. Sword Man is SWORD.MAN.! Tengu Man has a super stupid voice but such a cool design and fighting style. Astro Man because... I like him. Also, that man is a grenade.
MM8 Worst: Fake Aqua Man, Search "Random as Fuck" Man, and "JUMP JUMP! SLIDE SLIDE!" No, but big snowy gets a pass for being a big lovable goofball.
MM9 Best: Galaxy Man. He is the best robot master. He is perfect. LOVE HIM!
MM9 Worst: As stupid as Tornado Man looks... it's Plug Man..... HIS NAME IS PLUG MAN!
MM10 Best: Sheep Man. Yes, he's incredibly stupid... but he's a sheep that's a storm cloud, and he looks like THAT, and I love him. Also Solar Man, because he's awesome.
MM10 Worst: Toss up. Strike Man might be the DUMBEST Robot Master design ever, but I kind of love how unapologetically stupid he is. Chill Man might be the laziest design ever with absolutely NO interesting qualities. Nitro Man isn't bad but he's kind of a boring rehash of Turbo Man. Wait, no... it's Pump Man. Look at him, he's a water pump. HE IS A WALKING WATER PUMP!