In Megaman 2 for NES there is an awesome trick for getting max lives. Here are the steps. I will maybe add a youtube video later:
Step One: Pass the Wood man stage (and it works well if you get metal man’s weapon first). You need the leaf shield to do the max lives trick.
In order to pass Woodman stage quick, you can use the blaster or better yet, easily pass Metal man stage.
Then use the Metal man saw blade power to quickly pass Woodmans stage and defeat Woodman with the metalman saw blade.
Step Two: Get to Airman stage where the mech birds drop eggs.
Then just put on your leaf shield and leave your controller and game untouched for a few hours, likely overnight. The little birds in the eggs will drop powerups including periodic one ups.
If you play the game on switch you might need to adjust your screen saver settings and keep your switch plugged in.