Mildly Frequent Megaman Factsさんのイラストまとめ

Dr. Wily is punk as fuck and as such has an affinity for skulls. where his pajamas and even his mug are skulls.

Oddly enough, he doesn't seem to notice Skullman that much, since he instead has a big hard-on for Gutsman

There's a Megaman 9 easter egg hidden in it's endless mode that's apparently yet undiscovered.
CAPCOM stated there's a secret hidden in the Endlees Mode of MM9 that hasn't found yet, believed to be a sort of killscreen. A theory is that CAPCOM lied but noone can confirm or deny.

BubbleMan has a design flaw that makes him unable to walk, underwater he's always swimming but on land he has to hop like a frog.

It's stated that Wily makes fun of this. To portray how "lame" he is, in the comics he's defeated by a weapon he'ss invulnerable to in the game.

TorchMan is a Robot Master from MM 11, thus he technically has no NetNavi counterpart, however, FireMan.EXE, based on FireMan from MM1 was renamed "TorchMan.EXE" in the anime MegaMan NT Warrior.

TorchMan also appears in the DOS version of MM3, where he looks like a lame MetalMan

TrinitroMan (Left) is a Robot Master from the fangame MegaMan Unlimited, this Robot Master originally was named "NitroMan", but then MegaMan 10 came along with an official NitroMan (Right), due to them sharing the same name, the RM from the Fangame was renamed.

Metalman is a Robot Master from MM2 that is famously known for being weak to his own weapon, also his weapon breaks the game completely.

This was originally done as a "hidden trick" to ensure players could discover something new upon replaying this game.

He is not a dentist.

Those are all of Sonic Man's weapons! As a bonus, the Egg Laser is Sonic Man's weakness and upon being hit by it, he turns back into Sonic.

That looks like a HOMING SHOT, BE CAREFUL SON-- Ehem-- The Homing Shot is a shot that homes in on enemies (duh), it is a reference to Sonic's move "Homing Attack" in which Sonic homes in a Spin Jump into his enemies.

Ring Launcher: Sonic throws rings which constrain and incapacitate his foes. While Sonic normally does not throw rings to attack, instances of rings being thrown have occurred before. Tails throws fake rings in Heroes and 06. Sonic throws a ring he can follow in Sonic Battle.

Fire Dasher & Thunder Dasher: These are Fire and Thunder variations of the Spin Dasher. these are most likely based on Sonic's elemental shields from the classic games.