NOTE: If an image appears to be missing, right click and and open it in a new tab. Steam tends to mess up loading when there are so many images.
The sections are divided by game, obviously.

Do not forget about the Mega Buster when facing bosses once you have other weapons. Just because a boss is weaker to another weapon does not mean that weapon is the only or sometimes even the best solution. There are several instances where I found the Mega Buster way more useful than the actual weakness. If I listed the mega buster in the weapons to use, it is because I found the boss is actual weak to it or it was incredibly easy to use it over the normal method.

~☆》 For those who are playing both collections, I also have a guide for the first.
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1155931415
This collection included a reduced damage mode. If you're having issues due to the high damage out put of the enemies, go into the legacy collection options and turn on armor mode.

My personal Boss Order: Cloudman-> Junkman-> Iceman-> Burstman-> Shademan-> Springman-> Slashman-> Turboman.
Some weaknesses are based on ease of use over damage.

Accessible by pressing w on keyboard/ Start/Options PS controller or Xbox controller

Go to Springman's stage and continue until you read the junction in the image.

From there continue up following the images, and -if you have it- Rush Jet can be super helpful.

Once obtained, you must turn in the Hyper Bolt to Auto. The Hyper Bolt cuts the price of the regular items in half and allows you to purchase 5 additional upgrade items . Some of them can be found for free in stages.

In this Collection only Megaman 7 had a password system

Use Rush Search before Robot Master battles every stage to effortlessly gather Energy Tanks, Weapon Tanks, Special Tanks, Lives, and Bolts!

An alternate and faster method is to go to Cloudman's stage and kill the bots that spawn from the dropped egg. You can walk back to the ladder and then go forward again to make it respawn.

My personal Boss Order: Tenguman-> Clownman-> Grenademan-> Frostman-> Swordman-> Searchman-> Astroman-> Aquaman.
Some weaknesses are based on ease of use over damage.

You can equip 1 part from the table below.

You can equip as many parts as you can afford from the table below.

I personally recommend these parts in this order.

• Arrow Shot -5 Bolts
  
• Energy Balancer -5 Bolts
  
• Hyper Speed Charge -7 Bolts
  
• Power Shield -6 Bolts
  
• Super Recover -5 Bolts

Total Cost -28 Bolts

This gives you 12 Bolts to spend as you see fit. The listed parts can easily get you through the game. This also leaves plenty of Bolts for the Laser Shot part if you're having issues with Green Devil.

There are a total of 40 bolts that can be used as currency for upgrades. Roll sells many upgrades for a set amounts of bolts.

Rockman/Megaman: Concreteman-> Galaxyman-> Hornetman-> Splashwoman-> Jewelman-> Plugman-> Tornadoman-> Magmaman.

Blues/Protoman: Galaxyman-> Hornetman-> Splashwoman-> Concreteman-> Jewelman-> Plugman-> Tornadoman-> Magmaman.
Some weaknesses are based on ease of use over damage.

Protoman does not have access to the store.

Rockman/Megaman: Sheepman-> Pumpman-> Solarman-> Chillman-> Nitroman-> Commandoman-> Blademan-> Strikeman

Blues/Protoman: Solarman-> Chillman-> Nitroman-> Commandoman-> Blademan-> Strikeman-> Sheepman-> Pumpman

Forte/Bass: Blademan-> Strikeman-> Sheepman-> Pumpman-> Solarman-> Chillman-> Nitroman-> Commandoman
Some weaknesses are based on ease of use over damage.

Only Rockman/Megaman can access this shop.

Only Blues/Protoman can access this shop.

Only Forte/Bass can access this shop.

I hope this provided the information you were looking for.
Please rate up if you like.