It doesn't seem like these are your original assets, so charging for them is just wrong.
For example the weapons tiles can be found here:
https://www.deviantart.com/thkaspar/art/1-Bit-Icons-682254106
In addition, your license terms requiring to link to "your" asset on itch.io which is "better than losing money" (implying you will sue someone for some sprites?) is just in really bad taste.