NES Screen Tool is very useful utility for designing screens for NES/Famicom games. You load pre-designed character ROM banks of a certain size and use them to build a screen, palettes, and attribute tables. You can also edit the character ROM tiles as needed.

It’s very useful for building single screens such as title screens, where you build the screen, then trim it, adjust the data slightly, and insert back into the ROM.

It’s more meant to be used in a NES demo/game from scratch. Although, as I explained above, it can be used for hacking purposes as well.

There is also an RLE option, and the code to use in a NES demo/game and can perhaps be used in a hacked game as well. Will take some modification. Utility source code is in the archive.