Do assets or monster groups take up rom space? (Solved)

Do things like that take up rom space or are they only used by nesmaker. Also what other notable main features dont take up rom space if any?

Assets don't take up any space in ROM, since they're just a user-friendly way to paint the screen with nametable + attribute data. The assets and asset groups are tool-only, the structure doesn't carry over to the game itself. Monster groups I'm not as sure.
For NESmaker 4.1.5, banks by default carry these types of data:

00-07 - Overworld screen data
08-0F - Underworld screen data
10 - Background graphics 01
11 - Background graphics 02
12 - Background graphics 03
13 - Monster object graphics 01
14 - Databank1
15 - Monster object graphics 00
16 - Palettes and nametable pointers
17 - Text
18-1A - Empty
1B - Music data and sound engine
1C - Object animation data
1D - Game object, HUD, Start + Win screen graphics
1E - Start + Win screen nametables
1F - Static bank - Main game loop, NMI, and initialization stuff

Awesome. Thanks cutter.